When a POST request comes through AJP and the request exceeds the max-post-size limit (maxEntitySize), Undertow's AjpServerRequestConduit implementation closes a connection without sending any response to the client/proxy. This behavior results in that a front-end proxy marking the backend worker (application server) as an error state and not forward requests to the worker for a while. In mod_cluster, this continues until the next STATUS request (10 seconds intervals) from the application server updates the server state. So, in the worst case, it can result in "All workers are in error state" and mod_cluster responds "503 Service Unavailable" for a while (up to 10 seconds). In mod_proxy_balancer, it does not forward requests to the worker until the "retry" timeout passes. However, luckily, mod_proxy_balancer has "forcerecovery" setting (On by default; this parameter can force the immediate recovery of all workers without considering the retry parameter of the workers if all workers of a balancer are in error state.). So, unlike mod_cluster, mod_proxy_balancer does not result in responding "503 Service Unavailable". An attacker could use this behavior to send a malicious request and trigger server errors, resulting in DoS (denial of service). This flaw was fixed in Undertow 2.2.19.Final, Undertow 2.3.0.Alpha2.

A flaw was found in 389 Directory Server. A specially crafted search query could lead to excessive CPU consumption in the do_search() function. An unauthenticated attacker could use this flaw to provoke a denial of service.

A flaw was found in 389-ds-base before version 1.3.8.4-13. The process ns-slapd crashes in delete_passwdPolicy function when persistent search connections are terminated unexpectedly leading to remote denial of service.

A flaw was found in glusterfs server through versions 4.1.4 and 3.1.2 which allowed repeated usage of GF_META_LOCK_KEY xattr. A remote, authenticated attacker could use this flaw to create multiple locks for single inode by using setxattr repetitively resulting in memory exhaustion of glusterfs server node.

The Gluster file system through versions 4.1.4 and 3.1.2 is vulnerable to a denial of service attack via use of the 'GF_XATTR_IOSTATS_DUMP_KEY' xattr. A remote, authenticated attacker could exploit this by mounting a Gluster volume and repeatedly calling 'setxattr(2)' to trigger a state dump and create an arbitrary number of files in the server's runtime directory.

A flaw was found in Undertow. A potential security issue in flow control handling by the browser over HTTP/2 may cause overhead or a denial of service in the server. This flaw exists because of an incomplete fix for CVE-2021-3629.

A vulnerability was found in CRI-O that causes memory or disk space exhaustion on the node for anyone with access to the Kube API. The ExecSync request runs commands in a container and logs the output of the command. This output is then read by CRI-O after command execution, and it is read in a manner where the entire file corresponding to the output of the command is read in. Thus, if the output of the command is large it is possible to exhaust the memory or the disk space of the node when CRI-O reads the output of the command. The highest threat from this vulnerability is system availability.

A flaw was found in vscode-xml in versions prior to 0.19.0. Schema download could lead to blind SSRF or DoS via a large file.

By specially crafting HTTP/2 requests, workers would be allocated 60 seconds longer than necessary, leading to worker exhaustion and a denial of service. Fixed in Apache HTTP Server 2.4.34 (Affected 2.4.18-2.4.30,2.4.33).

Node.js: All versions prior to Node.js 6.15.0, 8.14.0, 10.14.0 and 11.3.0: Denial of Service with large HTTP headers: By using a combination of many requests with maximum sized headers (almost 80 KB per connection), and carefully timed completion of the headers, it is possible to cause the HTTP server to abort from heap allocation failure. Attack potential is mitigated by the use of a load balancer or other proxy layer.

It was found that URLResource.getLastModified() in Undertow closes the file descriptors only when they are finalized which can cause file descriptors to exhaust. This leads to a file handler leak.

An uncontrolled resource consumption flaw has been discovered in redhat-certification in the way documents are loaded. A remote attacker may provide an existing but invalid XML file which would be opened and never closed, possibly producing a Denial of Service.

redhat-certification 7 does not properly restrict the number of recursive definitions of entities in XML documents, allowing an unauthenticated user to run a "Billion Laugh Attack" by replying to XMLRPC methods when getting the status of an host.

A flaw was found in the 389 Directory Server that allows users to cause a crash in the LDAP server using ldapsearch with server side sort.

libvirt version before 4.2.0-rc1 is vulnerable to a resource exhaustion as a result of an incomplete fix for CVE-2018-5748 that affects QEMU monitor but now also triggered via QEMU guest agent.

Memcached version 1.5.5 contains an Insufficient Control of Network Message Volume (Network Amplification, CWE-406) vulnerability in the UDP support of the memcached server that can result in denial of service via network flood (traffic amplification of 1:50,000 has been reported by reliable sources). This attack appear to be exploitable via network connectivity to port 11211 UDP. This vulnerability appears to have been fixed in 1.5.6 due to the disabling of the UDP protocol by default.

There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.

A vulnerability stemming from failure to properly clean up closed OMAPI connections can lead to exhaustion of the pool of socket descriptors available to the DHCP server. Affects ISC DHCP 4.1.0 to 4.1-ESV-R15, 4.2.0 to 4.2.8, 4.3.0 to 4.3.6. Older versions may also be affected but are well beyond their end-of-life (EOL). Releases prior to 4.1.0 have not been tested.

An uncontrolled resource consumption flaw was found in openstack-neutron. This flaw allows a remote authenticated user to query a list of security groups for an invalid project. This issue creates resources that are unconstrained by the user's quota. If a malicious user were to submit a significant number of requests, this could lead to a denial of service.

The mod_proxy_ajp module in the Apache HTTP Server before 2.2.21, when used with mod_proxy_balancer in certain configurations, allows remote attackers to cause a denial of service (temporary "error state" in the backend server) via a malformed HTTP request.

A flaw was found in dpdk. This flaw allows a malicious vhost-user master to attach an unexpected number of fds as ancillary data to VHOST_USER_GET_INFLIGHT_FD / VHOST_USER_SET_INFLIGHT_FD messages that are not closed by the vhost-user slave. By sending such messages continuously, the vhost-user master exhausts available fd in the vhost-user slave process, leading to a denial of service.

The Network Lock Manager (NLM) protocol implementation in the NFS client functionality in the Linux kernel before 3.0 allows local users to cause a denial of service (system hang) via a LOCK_UN flock system call.

The gfs2_fallocate function in fs/gfs2/file.c in the Linux kernel before 3.0-rc1 does not ensure that the size of a chunk allocation is a multiple of the block size, which allows local users to cause a denial of service (BUG and system crash) by arranging for all resource groups to have too little free space.

net/core/net_namespace.c in the Linux kernel 2.6.32 and earlier does not properly handle a high rate of creation and cleanup of network namespaces, which makes it easier for remote attackers to cause a denial of service (memory consumption) via requests to a daemon that requires a separate namespace per connection, as demonstrated by vsftpd.

A flaw was found in libwebp in versions before 1.0.1. When reading a file libwebp allocates an excessive amount of memory. The highest threat from this vulnerability is to the service availability.

A vulnerability was found in Undertow. This vulnerability impacts a server that supports the wildfly-http-client protocol. Whenever a malicious user opens and closes a connection with the HTTP port of the server and then closes the connection immediately, the server will end with both memory and open file limits exhausted at some point, depending on the amount of memory available. At HTTP upgrade to remoting, the WriteTimeoutStreamSinkConduit leaks connections if RemotingConnection is closed by Remoting ServerConnectionOpenListener. Because the remoting connection originates in Undertow as part of the HTTP upgrade, there is an external layer to the remoting connection. This connection is unaware of the outermost layer when closing the connection during the connection opening procedure. Hence, the Undertow WriteTimeoutStreamSinkConduit is not notified of the closed connection in this scenario. Because WriteTimeoutStreamSinkConduit creates a timeout task, the whole dependency tree leaks via that task, which is added to XNIO WorkerThread. So, the workerThread points to the Undertow conduit, which contains the connections and causes the leak.