In WAGO I/O-Check Service in multiple products an unauthenticated remote attacker can send a specially crafted packet containing OS commands to provoke a denial of service.

When BIG-IP AFM is provisioned with IPS module enabled and protocol inspection profile is configured on a virtual server or firewall rule or policy, undisclosed traffic can cause an increase in CPU resource utilization.   Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

@fastify/multipart is a Fastify plugin for parsing the multipart content-type. Prior to versions 8.3.1 and 9.0.3, the `saveRequestFiles` function does not delete the uploaded temporary files when user cancels the request. The issue is fixed in versions 8.3.1 and 9.0.3. As a workaround, do not use `saveRequestFiles`.

There is a resource management error vulnerability in eCNS280_TD V100R005C10SPC650. An attacker needs to perform specific operations to exploit the vulnerability on the affected device. Due to improper resource management of the function, the vulnerability can be exploited to cause service abnormal on affected devices.

ESXi contains a slow HTTP POST denial-of-service vulnerability in rhttpproxy. A malicious actor with network access to ESXi may exploit this issue to create a denial-of-service condition by overwhelming rhttpproxy service with multiple requests.

VMware Workspace ONE UEM REST API contains a denial of service vulnerability. A malicious actor with access to /API/system/admins/session could cause an API denial of service due to improper rate limiting.

Crash in USB HID dissector in Wireshark 3.4.0 to 3.4.2 allows denial of service via packet injection or crafted capture file

A vulnerability has been discovered in Citrix ADC (formerly known as NetScaler ADC) and Citrix Gateway (formerly known as NetScaler Gateway), and Citrix SD-WAN WANOP Edition models 4000-WO, 4100-WO, 5000-WO, and 5100-WO. These vulnerabilities, if exploited, could lead to the limited available disk space on the appliances being fully consumed.

A vulnerability in the email scanning algorithm of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to perform a denial of service (DoS) attack against an affected device. This vulnerability is due to insufficient input validation of incoming emails. An attacker could exploit this vulnerability by sending a crafted email through Cisco ESA. A successful exploit could allow the attacker to exhaust all the available CPU resources on an affected device for an extended period of time, preventing other emails from being processed and resulting in a DoS condition.

Http4s (http4s-blaze-server) is a minimal, idiomatic Scala interface for HTTP services. Http4s before versions 0.21.17, 0.22.0-M2, and 1.0.0-M14 have a vulnerability which can lead to a denial-of-service. Blaze-core, a library underlying http4s-blaze-server, accepts connections unboundedly on its selector pool. This has the net effect of amplifying degradation in services that are unable to handle their current request load, since incoming connections are still accepted and added to an unbounded queue. Each connection allocates a socket handle, which drains a scarce OS resource. This can also confound higher level circuit breakers which work based on detecting failed connections. http4s provides a general "MaxActiveRequests" middleware mechanism for limiting open connections, but it is enforced inside the Blaze accept loop, after the connection is accepted and the socket opened. Thus, the limit only prevents the number of connections which can be simultaneously processed, not the number of connections which can be held open. In 0.21.17, 0.22.0-M2, and 1.0.0-M14, a new "maxConnections" property, with a default value of 1024, has been added to the `BlazeServerBuilder`. Setting the value to a negative number restores unbounded behavior, but is strongly disrecommended. The NIO2 backend does not respect `maxConnections`. Its use is now deprecated in http4s-0.21, and the option is removed altogether starting in http4s-0.22. There are several possible workarounds described in the refrenced GitHub Advisory GHSA-xhv5-w9c5-2r2w.

On WAGO PFC200 devices in different firmware versions with special crafted packets an attacker with network access to the device could cause a denial of service for the login service of the runtime.

A memory leak exists in Palo Alto Networks PAN-OS software that enables an attacker to send a burst of crafted packets through the firewall that eventually prevents the firewall from processing traffic. This issue applies only to PA-5400 Series devices that are running PAN-OS software with the SSL Forward Proxy feature enabled.

blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. All servers running blaze-core before version 0.14.15 are affected by a vulnerability in which unbounded connection acceptance leads to file handle exhaustion. Blaze, accepts connections unconditionally on a dedicated thread pool. This has the net effect of amplifying degradation in services that are unable to handle their current request load, since incoming connections are still accepted and added to an unbounded queue. Each connection allocates a socket handle, which drains a scarce OS resource. This can also confound higher level circuit breakers which work based on detecting failed connections. The vast majority of affected users are using it as part of http4s-blaze-server <= 0.21.16. http4s provides a mechanism for limiting open connections, but is enforced inside the Blaze accept loop, after the connection is accepted and the socket opened. Thus, the limit only prevents the number of connections which can be simultaneously processed, not the number of connections which can be held open. The issue is fixed in version 0.14.15 for "NIO1SocketServerGroup". A "maxConnections" parameter is added, with a default value of 512. Concurrent connections beyond this limit are rejected. To run unbounded, which is not recommended, set a negative number. The "NIO2SocketServerGroup" has no such setting and is now deprecated. There are several possible workarounds described in the refrenced GitHub Advisory GHSA-xmw9-q7x9-j5qc.

An issue was discovered in Foxit Reader and PhantomPDF before 9.7. It allows memory consumption because data is created for each page of an application level.

SSH servers which implement file transfer protocols are vulnerable to a denial of service attack from clients which complete the key exchange slowly, or not at all, causing pending content to be read into memory, but never transmitted.

An issue in the sql_trans_copy_key component of MonetDB Server v11.45.17 and v11.46.0 allows attackers to cause a Denial of Service (DoS) via crafted SQL statements.

An issue was discovered in Django 3.2 before 3.2.23, 4.1 before 4.1.13, and 4.2 before 4.2.7. The NFKC normalization is slow on Windows. As a consequence, django.contrib.auth.forms.UsernameField is subject to a potential DoS (denial of service) attack via certain inputs with a very large number of Unicode characters.

Botan is a C++ cryptography library. X.509 certificates can identify elliptic curves using either an object identifier or using explicit encoding of the parameters. Prior to versions 3.3.0 and 2.19.4, an attacker could present an ECDSA X.509 certificate using explicit encoding where the parameters are very large. The proof of concept used a 16Kbit prime for this purpose. When parsing, the parameter is checked to be prime, causing excessive computation. This was patched in 2.19.4 and 3.3.0 to allow the prime parameter of the elliptic curve to be at most 521 bits. No known workarounds are available. Note that support for explicit encoding of elliptic curve parameters is deprecated in Botan.

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Thread Pooling). Supported versions that are affected are 8.0.39 and prior, 8.4.2 and prior and 9.0.1 and prior. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Redis is an open source, in-memory database that persists on disk. In versions starting at 2.6 and prior to 7.4.3, An unauthenticated client can cause unlimited growth of output buffers, until the server runs out of memory or is killed. By default, the Redis configuration does not limit the output buffer of normal clients (see client-output-buffer-limit). Therefore, the output buffer can grow unlimitedly over time. As a result, the service is exhausted and the memory is unavailable. When password authentication is enabled on the Redis server, but no password is provided, the client can still cause the output buffer to grow from "NOAUTH" responses until the system will run out of memory. This issue has been patched in version 7.4.3. An additional workaround to mitigate this problem without patching the redis-server executable is to block access to prevent unauthenticated users from connecting to Redis. This can be done in different ways. Either using network access control tools like firewalls, iptables, security groups, etc, or enabling TLS and requiring users to authenticate using client side certificates.

EMQ X Broker versions prior to 4.2.8 are vulnerable to a denial of service attack as a result of excessive memory consumption due to the handling of untrusted inputs. These inputs cause the message broker to consume large amounts of memory, resulting in the application being terminated by the operating system.

plone.rest allows users to use HTTP verbs such as GET, POST, PUT, DELETE, etc. in Plone. Starting in the 2.x branch and prior to versions 2.0.1 and 3.0.1, when the `++api++` traverser is accidentally used multiple times in a url, handling it takes increasingly longer, making the server less responsive. Patches are available in `plone.rest` 2.0.1 and 3.0.1. Series 1.x is not affected. As a workaround, one may redirect `/++api++/++api++` to `/++api++` in one's frontend web server (nginx, Apache).

An issue was discovered in Mattermost Server before 5.18.0. It allows attackers to cause a denial of service (memory consumption) via a large Slack import.

A vulnerability in the Internet Key Exchange version 2 (IKEv2) function of Cisco IOS XR Software could allow an unauthenticated, remote attacker to prevent an affected device from processing any control plane UDP packets.&nbsp; This vulnerability is due to improper handling of malformed IKEv2 packets. An attacker could exploit this vulnerability by sending malformed IKEv2 packets to an affected device. A successful exploit could allow the attacker to prevent the affected device from processing any control plane UDP packets, resulting in a denial of service (DoS) condition. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

A vulnerability in the HTTP/HTTPS service used by J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Captive Portal allows an unauthenticated attacker to cause an extended Denial of Service (DoS) for these services by sending a high number of specific requests. This issue affects: Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S17 on EX Series; 12.3X48 versions prior to 12.3X48-D105 on SRX Series; 15.1 versions prior to 15.1R7-S8; 15.1X49 versions prior to 15.1X49-D230 on SRX Series; 16.1 versions prior to 16.1R7-S8; 17.4 versions prior to 17.4R2-S12, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S6; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3; 18.4 versions prior to 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R2-S2, 19.1R3-S2; 19.2 versions prior to 19.2R1-S5, 19.2R3; 19.3 versions prior to 19.3R2-S4, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2-S2, 19.4R3; 20.1 versions prior to 20.1R1-S3, 20.1R2; 20.2 versions prior to 20.2R1-S1, 20.2R2.

Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.10, and 8.0.0 to 8.0.7 is vulnerable to certain types of HTTP/2 HEADERS frames that can cause the server to allocate a large amount of memory and spin the thread.

The Zone Controller service in the Zoom On-Premise Meeting Connector Controller before version 4.6.358.20210205 does not verify the cnt field sent in incoming network packets, which leads to exhaustion of resources and system crash.

An uncontrolled resource consumption vulnerability in Juniper Networks Junos OS on QFX5000 Series and EX4600 Series switches allows an attacker sending large amounts of legitimate traffic destined to the device to cause Interchassis Control Protocol (ICCP) interruptions, leading to an unstable control connection between the Multi-Chassis Link Aggregation Group (MC-LAG) nodes which can in turn lead to traffic loss. Continued receipt of this amount of traffic will create a sustained Denial of Service (DoS) condition. An indication that the system could be impacted by this issue is the following log message: "DDOS_PROTOCOL_VIOLATION_SET: Warning: Host-bound traffic for protocol/exception LOCALNH:aggregate exceeded its allowed bandwidth at fpc <fpc number> for <n> times, started at <timestamp>" This issue affects Juniper Networks Junos OS on QFX5000 Series and EX4600 Series: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R2-S13, 17.4R3-S5; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S8, 18.4R3-S7; 19.1 versions prior to 19.1R3-S5; 19.2 versions prior to 19.2R1-S6, 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R1-S1, 20.4R2.

IKTeam BearFTP before 0.2.0 allows remote attackers to achieve denial of service via a large volume of connections to the PASV mode port.

Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 affects all Kirby sites with user accounts (unless Kirby's API and Panel are disabled in the config). The real-world impact of this vulnerability is limited, however we still recommend to update to one of the patch releases because they also fix more severe vulnerabilities. Kirby's authentication endpoint did not limit the password length. This allowed attackers to provide a password with a length up to the server's maximum request body length. Validating that password against the user's actual password requires hashing the provided password, which requires more CPU and memory resources (and therefore processing time) the longer the provided password gets. This could be abused by an attacker to cause the website to become unresponsive or unavailable. Because Kirby comes with a built-in brute force protection, the impact of this vulnerability is limited to 10 failed logins from each IP address and 10 failed logins for each existing user per hour. The problem has been patched in Kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6. In all of the mentioned releases, the maintainers have added password length limits in the affected code so that passwords longer than 1000 bytes are immediately blocked, both when setting a password and when logging in.

An issue has been discovered in GitLab CE/EE affecting all versions from 8.13 before 17.10.7, 17.11 before 17.11.3, and 18.0 before 18.0.1. A lack of input validation in Board Names could be used to trigger a denial of service.

A vulnerability has been identified in RUGGEDCOM i800, RUGGEDCOM i800NC, RUGGEDCOM i801, RUGGEDCOM i801NC, RUGGEDCOM i802, RUGGEDCOM i802NC, RUGGEDCOM i803, RUGGEDCOM i803NC, RUGGEDCOM M2100, RUGGEDCOM M2100F, RUGGEDCOM M2100NC, RUGGEDCOM M2200, RUGGEDCOM M2200F, RUGGEDCOM M2200NC, RUGGEDCOM M969, RUGGEDCOM M969F, RUGGEDCOM M969NC, RUGGEDCOM RMC30, RUGGEDCOM RMC30NC, RUGGEDCOM RMC8388 V4.X, RUGGEDCOM RMC8388 V5.X, RUGGEDCOM RMC8388NC V4.X, RUGGEDCOM RMC8388NC V5.X, RUGGEDCOM RP110, RUGGEDCOM RP110NC, RUGGEDCOM RS1600, RUGGEDCOM RS1600F, RUGGEDCOM RS1600FNC, RUGGEDCOM RS1600NC, RUGGEDCOM RS1600T, RUGGEDCOM RS1600TNC, RUGGEDCOM RS400, RUGGEDCOM RS400F, RUGGEDCOM RS400NC, RUGGEDCOM RS401, RUGGEDCOM RS401NC, RUGGEDCOM RS416, RUGGEDCOM RS416F, RUGGEDCOM RS416NC, RUGGEDCOM RS416NCv2 V4.X, RUGGEDCOM RS416NCv2 V5.X, RUGGEDCOM RS416P, RUGGEDCOM RS416PF, RUGGEDCOM RS416PNC, RUGGEDCOM RS416PNCv2 V4.X, RUGGEDCOM RS416PNCv2 V5.X, RUGGEDCOM RS416Pv2 V4.X, RUGGEDCOM RS416Pv2 V5.X, RUGGEDCOM RS416v2 V4.X, RUGGEDCOM RS416v2 V5.X, RUGGEDCOM RS8000, RUGGEDCOM RS8000A, RUGGEDCOM RS8000ANC, RUGGEDCOM RS8000H, RUGGEDCOM RS8000HNC, RUGGEDCOM RS8000NC, RUGGEDCOM RS8000T, RUGGEDCOM RS8000TNC, RUGGEDCOM RS900, RUGGEDCOM RS900 (32M) V4.X, RUGGEDCOM RS900 (32M) V5.X, RUGGEDCOM RS900F, RUGGEDCOM RS900G, RUGGEDCOM RS900G (32M) V4.X, RUGGEDCOM RS900G (32M) V5.X, RUGGEDCOM RS900GF, RUGGEDCOM RS900GNC, RUGGEDCOM RS900GNC(32M) V4.X, RUGGEDCOM RS900GNC(32M) V5.X, RUGGEDCOM RS900GP, RUGGEDCOM RS900GPF, RUGGEDCOM RS900GPNC, RUGGEDCOM RS900L, RUGGEDCOM RS900LNC, RUGGEDCOM RS900M-GETS-C01, RUGGEDCOM RS900M-GETS-XX, RUGGEDCOM RS900M-STND-C01, RUGGEDCOM RS900M-STND-XX, RUGGEDCOM RS900MNC-GETS-C01, RUGGEDCOM RS900MNC-GETS-XX, RUGGEDCOM RS900MNC-STND-XX, RUGGEDCOM RS900MNC-STND-XX-C01, RUGGEDCOM RS900NC, RUGGEDCOM RS900NC(32M) V4.X, RUGGEDCOM RS900NC(32M) V5.X, RUGGEDCOM RS900W, RUGGEDCOM RS910, RUGGEDCOM RS910L, RUGGEDCOM RS910LNC, RUGGEDCOM RS910NC, RUGGEDCOM RS910W, RUGGEDCOM RS920L, RUGGEDCOM RS920LNC, RUGGEDCOM RS920W, RUGGEDCOM RS930L, RUGGEDCOM RS930LNC, RUGGEDCOM RS930W, RUGGEDCOM RS940G, RUGGEDCOM RS940GF, RUGGEDCOM RS940GNC, RUGGEDCOM RS969, RUGGEDCOM RS969NC, RUGGEDCOM RSG2100, RUGGEDCOM RSG2100 (32M) V4.X, RUGGEDCOM RSG2100 (32M) V5.X, RUGGEDCOM RSG2100F, RUGGEDCOM RSG2100NC, RUGGEDCOM RSG2100NC(32M) V4.X, RUGGEDCOM RSG2100NC(32M) V5.X, RUGGEDCOM RSG2100P, RUGGEDCOM RSG2100P (32M) V4.X, RUGGEDCOM RSG2100P (32M) V5.X, RUGGEDCOM RSG2100PF, RUGGEDCOM RSG2100PNC, RUGGEDCOM RSG2100PNC (32M) V4.X, RUGGEDCOM RSG2100PNC (32M) V5.X, RUGGEDCOM RSG2200, RUGGEDCOM RSG2200F, RUGGEDCOM RSG2200NC, RUGGEDCOM RSG2288 V4.X, RUGGEDCOM RSG2288 V5.X, RUGGEDCOM RSG2288NC V4.X, RUGGEDCOM RSG2288NC V5.X, RUGGEDCOM RSG2300 V4.X, RUGGEDCOM RSG2300 V5.X, RUGGEDCOM RSG2300F, RUGGEDCOM RSG2300NC V4.X, RUGGEDCOM RSG2300NC V5.X, RUGGEDCOM RSG2300P V4.X, RUGGEDCOM RSG2300P V5.X, RUGGEDCOM RSG2300PF, RUGGEDCOM RSG2300PNC V4.X, RUGGEDCOM RSG2300PNC V5.X, RUGGEDCOM RSG2488 V4.X, RUGGEDCOM RSG2488 V5.X, RUGGEDCOM RSG2488F, RUGGEDCOM RSG2488NC V4.X, RUGGEDCOM RSG2488NC V5.X, RUGGEDCOM RSG907R, RUGGEDCOM RSG908C, RUGGEDCOM RSG909R, RUGGEDCOM RSG910C, RUGGEDCOM RSG920P V4.X, RUGGEDCOM RSG920P V5.X, RUGGEDCOM RSG920PNC V4.X, RUGGEDCOM RSG920PNC V5.X, RUGGEDCOM RSL910, RUGGEDCOM RSL910NC, RUGGEDCOM RST2228, RUGGEDCOM RST2228P, RUGGEDCOM RST916C, RUGGEDCOM RST916P. The web server of the affected devices contains a vulnerability that may lead to a denial of service condition. An attacker may cause total loss of availability of the web server, which might recover after the attack is over.

VerneMQ MQTT Broker versions prior to 1.12.0 are vulnerable to a denial of service attack as a result of excessive memory consumption due to the handling of untrusted inputs. These inputs cause the message broker to consume large amounts of memory, resulting in the application being terminated by the operating system.

CNCF Envoy through 1.13.0 may consume excessive amounts of memory when proxying HTTP/1.1 requests or responses with many small (i.e. 1 byte) chunks.

An issue was discovered in Mattermost Server before 5.8.0, 5.7.2, 5.6.5, and 4.10.7. It allows attackers to cause a denial of service (memory consumption) via OpenGraph.

A buffer-management vulnerability in OPC Foundation OPCFoundation.NetStandard.Opc.Ua.Core before 1.05.374.54 could allow remote attackers to exhaust memory resources. It is triggered when the system receives an excessive number of messages from a remote source. This could potentially lead to a denial of service (DoS) condition, disrupting the normal operation of the system.

HashiCorp Consul and Consul Enterprise up to 1.6.2 HTTP/RPC services allowed unbounded resource usage, and were susceptible to unauthenticated denial of service. Fixed in 1.6.3.

The O-RAN E2T I-Release Prometheus metric Increment function can crash in sctpThread.cpp for message.peerInfo->sctpParams->e2tCounters[IN_SUCC][MSG_COUNTER][ProcedureCode_id_RICsubscription]->Increment().

Sydent is a reference Matrix identity server. Sydent does not limit the size of requests it receives from HTTP clients. A malicious user could send an HTTP request with a very large body, leading to memory exhaustion and denial of service. Sydent also does not limit response size for requests it makes to remote Matrix homeservers. A malicious homeserver could return a very large response, again leading to memory exhaustion and denial of service. This affects any server which accepts registration requests from untrusted clients. This issue has been patched by releases 89071a1, 0523511, f56eee3. As a workaround request sizes can be limited in an HTTP reverse-proxy. There are no known workarounds for the problem with overlarge responses.

The ppp decapsulator in tcpdump 4.9.3 can be convinced to allocate a large amount of memory.

CiphertextHeader.java in Cryptacular 1.2.3, as used in Apereo CAS and other products, allows attackers to trigger excessive memory allocation during a decode operation, because the nonce array length associated with "new byte" may depend on untrusted input within the header of encoded data.

Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.5 and 6.0.19, a small amount of HTTP/2 traffic can lead to Suricata using a large amount of memory. The issue has been addressed in Suricata 7.0.5 and 6.0.19. Workarounds include disabling the HTTP/2 parser and reducing `app-layer.protocols.http2.max-table-size` value (default is 65536).

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.5.1, a malicious server can crash the FreeRDP client by sending invalid huge allocation size. Version 3.5.1 contains a patch for the issue. No known workarounds are available.

Pimcore is an Open Source Data & Experience Management Platform. The Pimcore thumbnail generation can be used to flood the server with large files. By changing the file extension or scaling factor of the requested thumbnail, attackers can create files that are much larger in file size than the original. This vulnerability is fixed in 11.2.4.

rizin before Release v0.6.3 is vulnerable to Uncontrolled Resource Consumption via bin_pe_parse_imports, Pe_r_bin_pe_parse_var, and estimate_slide.

Adacore Ada Web Server (AWS) before 25.2 is vulnerable to a denial-of-service (DoS) condition due to improper handling of SSL handshakes during connection initialization. When a client initiates an HTTPS connection, the server performs the SSL handshake before assigning the connection to a processing slot. However, there is no specific timeout set for this phase, and the server uses the default socket timeout, which is effectively infinite. An attacker can exploit this by sending a malformed TLS ClientHello message with incorrect length values. This causes the server to wait indefinitely for data that never arrives, blocking the worker thread (Line) handling the connection. By opening multiple such connections, up to the server's maximum limit, the attacker can exhaust all available working threads, preventing the server from handling new, legitimate requests.