The HTTP/2 implementation in Apache Tomcat 9.0.0.M1 to 9.0.14 and 8.5.0 to 8.5.37 accepted streams with excessive numbers of SETTINGS frames and also permitted clients to keep streams open without reading/writing request/response data. By keeping streams open for requests that utilised the Servlet API's blocking I/O, clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS.

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).

In Apache HTTP server versions 2.4.37 and prior, by sending request bodies in a slow loris way to plain resources, the h2 stream for that request unnecessarily occupied a server thread cleaning up that incoming data. This affects only HTTP/2 (mod_http2) connections.

CXF supports (via JwtRequestCodeFilter) passing OAuth 2 parameters via a JWT token as opposed to query parameters (see: The OAuth 2.0 Authorization Framework: JWT Secured Authorization Request (JAR)). Instead of sending a JWT token as a "request" parameter, the spec also supports specifying a URI from which to retrieve a JWT token from via the "request_uri" parameter. CXF was not validating the "request_uri" parameter (apart from ensuring it uses "https) and was making a REST request to the parameter in the request to retrieve a token. This means that CXF was vulnerable to DDos attacks on the authorization server, as specified in section 10.4.1 of the spec. This issue affects Apache CXF versions prior to 3.4.3; Apache CXF versions prior to 3.3.10.

qpid-cpp: ACL policies only loaded if the acl-file option specified enabling DoS by consuming all available file descriptors

Apache OpenMeetings 1.0.0 doesn't check contents of files being uploaded. An attacker can cause a denial of service by uploading multiple large files to the server.

Apache ATS 6.0.0 to 6.2.3, 7.0.0 to 7.1.9, and 8.0.0 to 8.0.6 is vulnerable to a HTTP/2 slow read attack.

When there are multiple ranges in a range request, Apache Traffic Server (ATS) will read the entire object from cache. This can cause performance problems with large objects in cache. This affects versions 6.0.0 to 6.2.2 and 7.0.0 to 7.1.3. To resolve this issue users running 6.x users should upgrade to 6.2.3 or later versions and 7.x users should upgrade to 7.1.4 or later versions.

Two four letter word commands "wchp/wchc" are CPU intensive and could cause spike of CPU utilization on Apache ZooKeeper server if abused, which leads to the server unable to serve legitimate client requests. Apache ZooKeeper thru version 3.4.9 and 3.5.2 suffer from this issue, fixed in 3.4.10, 3.5.3, and later.

The documentation of Apache Tomcat 10.1.0-M1 to 10.1.0-M14, 10.0.0-M1 to 10.0.20, 9.0.13 to 9.0.62 and 8.5.38 to 8.5.78 for the EncryptInterceptor incorrectly stated it enabled Tomcat clustering to run over an untrusted network. This was not correct. While the EncryptInterceptor does provide confidentiality and integrity protection, it does not protect against all risks associated with running over any untrusted network, particularly DoS risks.

The Security Team noticed that the termination condition of the for loop in the readExternal method is a controllable variable, which, if tampered with, may lead to CPU exhaustion. As a fix, we added an upper bound and termination condition in the read and write logic. We classify it as a "low-priority but useful improvement". SystemDS is a distributed system and needs to serialize/deserialize data but in many code paths (e.g., on Spark broadcast/shuffle or writing to sequence files) the byte stream is anyway protected by additional CRC fingerprints. In this particular case though, the number of decoders is upper-bounded by twice the number of columns, which means an attacker would need to modify two entries in the byte stream in a consistent manner. By adding these checks robustness was strictly improved with almost zero overhead. These code changes are available in versions higher than 2.2.1.

In Apache Thrift 0.9.3 to 0.13.0, malicious RPC clients could send short messages which would result in a large memory allocation, potentially leading to denial of service.

Some HTTP/2 implementations are vulnerable to a flood of empty frames, potentially leading to a denial of service. The attacker sends a stream of frames with an empty payload and without the end-of-stream flag. These frames can be DATA, HEADERS, CONTINUATION and/or PUSH_PROMISE. The peer spends time processing each frame disproportionate to attack bandwidth. This can consume excess CPU.

Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service. The attacker sends a stream of headers with a 0-length header name and 0-length header value, optionally Huffman encoded into 1-byte or greater headers. Some implementations allocate memory for these headers and keep the allocation alive until the session dies. This can consume excess memory.

Some HTTP/2 implementations are vulnerable to a settings flood, potentially leading to a denial of service. The attacker sends a stream of SETTINGS frames to the peer. Since the RFC requires that the peer reply with one acknowledgement per SETTINGS frame, an empty SETTINGS frame is almost equivalent in behavior to a ping. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both.

Some HTTP/2 implementations are vulnerable to window size manipulation and stream prioritization manipulation, potentially leading to a denial of service. The attacker requests a large amount of data from a specified resource over multiple streams. They manipulate window size and stream priority to force the server to queue the data in 1-byte chunks. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both.

Some HTTP/2 implementations are vulnerable to a reset flood, potentially leading to a denial of service. The attacker opens a number of streams and sends an invalid request over each stream that should solicit a stream of RST_STREAM frames from the peer. Depending on how the peer queues the RST_STREAM frames, this can consume excess memory, CPU, or both.

Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of service. The attacker opens the HTTP/2 window so the peer can send without constraint; however, they leave the TCP window closed so the peer cannot actually write (many of) the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the servers queue the responses, this can consume excess memory, CPU, or both.

Some HTTP/2 implementations are vulnerable to ping floods, potentially leading to a denial of service. The attacker sends continual pings to an HTTP/2 peer, causing the peer to build an internal queue of responses. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both.

Some HTTP/2 implementations are vulnerable to resource loops, potentially leading to a denial of service. The attacker creates multiple request streams and continually shuffles the priority of the streams in a way that causes substantial churn to the priority tree. This can consume excess CPU.

A vulnerability in the JsonMapObjectReaderWriter of Apache CXF allows an attacker to submit malformed JSON to a web service, which results in the thread getting stuck in an infinite loop, consuming CPU indefinitely. This issue affects Apache CXF versions prior to 3.4.4; Apache CXF versions prior to 3.3.11.

In Apache SpamAssassin before 3.4.3, a message can be crafted in a way to use excessive resources. Upgrading to SA 3.4.3 as soon as possible is the recommended fix but details will not be shared publicly.

In Apache Qpid Broker-J versions 6.1.0 through 6.1.4 (inclusive) the broker does not properly enforce a maximum frame size in AMQP 1.0 frames. A remote unauthenticated attacker could exploit this to cause the broker to exhaust all available memory and eventually terminate. Older AMQP protocols are not affected.

The read_request_line function in server/protocol.c in the Apache HTTP Server 2.4.12 does not initialize the protocol structure member, which allows remote attackers to cause a denial of service (NULL pointer dereference and process crash) by sending a request that lacks a method to an installation that enables the INCLUDES filter and has an ErrorDocument 400 directive specifying a local URI.

A Denial of Service vulnerability was found in Apache Qpid Broker-J versions 6.0.0-7.0.6 (inclusive) and 7.1.0 which allows an unauthenticated attacker to crash the broker instance by sending specially crafted commands using AMQP protocol versions below 1.0 (AMQP 0-8, 0-9, 0-91 and 0-10). Users of Apache Qpid Broker-J versions 6.0.0-7.0.6 (inclusive) and 7.1.0 utilizing AMQP protocols 0-8, 0-9, 0-91, 0-10 must upgrade to Qpid Broker-J versions 7.0.7 or 7.1.1 or later.

Apache Traffic Server 6.0.0 to 6.2.0 are affected by an HPACK Bomb Attack.

A vulnerability was found in Apache HTTP Server 2.4.17 to 2.4.38. Using fuzzed network input, the http/2 request handling could be made to access freed memory in string comparison when determining the method of a request and thus process the request incorrectly.

An access permission override in Apache Struts 2.0.0 to 2.5.20 may cause a Denial of Service when performing a file upload.

In Apache Subversion versions up to and including 1.9.10, 1.10.4, 1.12.0, Subversion's svnserve server process may exit when a client sends certain sequences of protocol commands. This can lead to disruption for users of the server.

In Apache Thrift 0.9.3 to 0.12.0, a server implemented in Go using TJSONProtocol or TSimpleJSONProtocol may panic when feed with invalid input data.

Vulnerability in the apr_psprintf function in the Apache Portable Runtime (APR) library for Apache 2.0.37 through 2.0.45 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via long strings, as demonstrated using XML objects to mod_dav, and possibly other vectors.

In Apache ActiveMQ 5.0.0 - 5.15.8, unmarshalling corrupt MQTT frame can lead to broker Out of Memory exception making it unresponsive.

The mod_dav_svn module for the Apache HTTP Server, as distributed in Apache Subversion before 1.6.17, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a request for a baselined WebDAV resource, as exploited in the wild in May 2011.

A Denial of Service vulnerability was found in Apache Qpid Broker-J versions 7.0.0-7.0.4 when AMQP protocols 0-8, 0-9 or 0-91 are used to publish messages with size greater than allowed maximum message size limit (100MB by default). The broker crashes due to the defect. AMQP protocols 0-10 and 1.0 are not affected.

Versions of Apache CXF Fediz prior to 1.4.4 do not fully disable Document Type Declarations (DTDs) when either parsing the Identity Provider response in the application plugins, or in the Identity Provider itself when parsing certain XML-based parameters.

Memory leak in the apr_brigade_split_line function in buckets/apr_brigade.c in the Apache Portable Runtime Utility library (aka APR-util) before 1.3.10, as used in the mod_reqtimeout module in the Apache HTTP Server and other software, allows remote attackers to cause a denial of service (memory consumption) via unspecified vectors related to the destruction of an APR bucket.

A carefully crafted invalid TLS handshake can cause Apache Traffic Server (ATS) to segfault. This affects version 6.2.2. To resolve this issue users running 6.2.2 should upgrade to 6.2.3 or later versions.

The (1) mod_cache and (2) mod_dav modules in the Apache HTTP Server 2.2.x before 2.2.16 allow remote attackers to cause a denial of service (process crash) via a request that lacks a path.

Apache Tomcat 7.0.0 through 7.0.6 and 6.0.0 through 6.0.30 does not enforce the maxHttpHeaderSize limit for requests involving the NIO HTTP connector, which allows remote attackers to cause a denial of service (OutOfMemoryError) via a crafted request.

In Apache HTTP Server versions 2.4.0 to 2.4.23, malicious input to mod_auth_digest can cause the server to crash, and each instance continues to crash even for subsequently valid requests.

The Cluster::deliveredEvent function in cluster/Cluster.cpp in Apache Qpid, as used in Red Hat Enterprise MRG before 1.3 and other products, allows remote attackers to cause a denial of service (daemon crash and cluster outage) via invalid AMQP data.

A bug exists in the way mod_ssl handled client renegotiations. A remote attacker could send a carefully crafted request that would cause mod_ssl to enter a loop leading to a denial of service. This bug can be only triggered with Apache HTTP Server version 2.4.37 when using OpenSSL version 1.1.1 or later, due to an interaction in changes to handling of renegotiation attempts.

The updatePosition function in lib/xmltok_impl.c in libexpat in Expat 2.0.1, as used in Python, PyXML, w3c-libwww, and other software, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with crafted UTF-8 sequences that trigger a buffer over-read, a different vulnerability than CVE-2009-2625.

By specially crafting HTTP requests, the mod_md challenge handler would dereference a NULL pointer and cause the child process to segfault. This could be used to DoS the server. Fixed in Apache HTTP Server 2.4.34 (Affected 2.4.33).

The big2_toUtf8 function in lib/xmltok.c in libexpat in Expat 2.0.1, as used in the XML-Twig module for Perl, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with malformed UTF-8 sequences that trigger a buffer over-read, related to the doProlog function in lib/xmlparse.c, a different vulnerability than CVE-2009-2625 and CVE-2009-3720.

In Apache ORC 1.0.0 to 1.4.3 a malformed ORC file can trigger an endlessly recursive function call in the C++ or Java parser. The impact of this bug is most likely denial-of-service against software that uses the ORC file parser. With the C++ parser, the stack overflow might possibly corrupt the stack.

Apache with mod_rewrite enabled on most UNIX systems allows remote attackers to bypass RewriteRules by inserting extra / (slash) characters into the requested path, which causes the regular expression in the RewriteRule to fail.

XMLScanner.java in Apache Xerces2 Java, as used in Sun Java Runtime Environment (JRE) in JDK and JRE 6 before Update 15 and JDK and JRE 5.0 before Update 20, and in other products, allows remote attackers to cause a denial of service (infinite loop and application hang) via malformed XML input, as demonstrated by the Codenomicon XML fuzzing framework.

The ap_proxy_ajp_request function in mod_proxy_ajp.c in mod_proxy_ajp in the Apache HTTP Server 2.2.x before 2.2.15 does not properly handle certain situations in which a client sends no request body, which allows remote attackers to cause a denial of service (backend server outage) via a crafted request, related to use of a 500 error code instead of the appropriate 400 error code.