Vulnerabilities (CVE)

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

HTTP/2 CONTINUATION DoS attack can cause Apache Traffic Server to consume more resources on the server.  Version from 8.0.0 through 8.1.9, from 9.0.0 through 9.2.3 are affected. Users can set a new setting (proxy.config.http2.max_continuation_frames_per_minute) to limit the number of CONTINUATION frames per minute.  ATS does have a fixed amount of memory a request can use and ATS adheres to these limits in previous releases. Users are recommended to upgrade to versions 8.1.10 or 9.2.4 which fix ... HTTP/2 CONTINUATION DoS attack can cause Apache Traffic Server to consume more resources on the server.  Version from 8.0.0 through 8.1.9, from 9.0.0 through 9.2.3 are affected. Users can set a new setting (proxy.config.http2.max_continuation_frames_per_minute) to limit the number of CONTINUATION frames per minute.  ATS does have a fixed amount of memory a request can use and ATS adheres to these limits in previous releases. Users are recommended to upgrade to versions 8.1.10 or 9.2.4 which fixes the issue.

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Invalid Accept-Encoding header can cause Apache Traffic Server to fail cache lookup and force forwarding requests. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.10, from 9.0.0 through 9.2.4. Users are recommended to upgrade to version 8.1.11 or 9.2.5, which fixes the issue.

Apache Traffic Server forwards malformed HTTP chunked trailer section to origin servers. This can be utilized for request smuggling and may also lead cache poisoning if the origin servers are vulnerable. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.10, from 9.0.0 through 9.2.4. Users can set a new setting (proxy.config.http.drop_chunked_trailers) not to forward chunked trailer section. Users are recommended to upgrade to version 8.1.11 or 9.2.5, which fixes the issue.

Apache Traffic Server accepts characters that are not allowed for HTTP field names and forwards malformed requests to origin servers. This can be utilized for request smuggling and may also lead cache poisoning if the origin servers are vulnerable. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.10, from 9.0.0 through 9.2.4. Users are recommended to upgrade to version 8.1.11 or 9.2.5, which fixes the issue.

Unchecked return value can allow Apache Traffic Server to retain privileges on startup. This issue affects Apache Traffic Server: from 9.2.0 through 9.2.5, from 10.0.0 through 10.0.1. Users are recommended to upgrade to version 9.2.6 or 10.0.2, which fixes the issue.

Improper Input Validation vulnerability in Apache Traffic Server. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.5. Users are recommended to upgrade to version 9.2.6, which fixes the issue, or 10.0.2, which does not have the issue.

Improper Input Validation vulnerability in HTTP/2 request validation of Apache Traffic Server allows an attacker to create smuggle or cache poison attacks. This issue affects Apache Traffic Server 8.0.0 to 9.1.2.

Improper Input Validation vulnerability in header parsing of Apache Traffic Server allows an attacker to request secure resources. This issue affects Apache Traffic Server 8.0.0 to 9.1.2.

ESI plugin does not have the limit for maximum inclusion depth, and that allows excessive memory consumption if malicious instructions are inserted. Users can use a new setting for the plugin (--max-inclusion-depth) to limit it. This issue affects Apache Traffic Server: from 10.0.0 through 10.0.5, from 9.0.0 through 9.2.10. Users are recommended to upgrade to version 9.2.11 or 10.0.6, which fixes the issue.

ACL configured in ip_allow.config or remap.config does not use IP addresses that are provided by PROXY protocol. Users can use a new setting (proxy.config.acl.subjects) to choose which IP addresses to use for the ACL if Apache Traffic Server is configured to accept PROXY protocol.  This issue affects undefined: from 10.0.0 through 10.0.6, from 9.0.0 through 9.2.10. Users are recommended to upgrade to version 9.2.11 or 10.0.6, which fixes the issue.

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Apache Traffic Server.This issue affects Apache Traffic Server: from 8.0.0 through 8.1.8, from 9.0.0 through 9.2.2. Users are recommended to upgrade to version 8.1.9 or 9.2.3, which fixes the issue.

Improper Input Validation vulnerability in Apache Traffic Server with malformed HTTP/2 frames.This issue affects Apache Traffic Server: from 9.0.0 through 9.2.2. Users are recommended to upgrade to version 9.2.3, which fixes the issue.

Valid Host header field can cause Apache Traffic Server to crash on some platforms. This issue affects Apache Traffic Server: from 9.2.0 through 9.2.5. Users are recommended to upgrade to version 9.2.6, which fixes the issue, or 10.0.2, which does not have the issue.

Improper Access Control vulnerability in Apache Traffic Server. This issue affects Apache Traffic Server: from 10.0.0 through 10.0.3. Users are recommended to upgrade to version 10.0.4, which fixes the issue.

Apache Traffic Server allows request smuggling if chunked messages are malformed.  This issue affects Apache Traffic Server: from 9.2.0 through 9.2.9, from 10.0.0 through 10.0.4. Users are recommended to upgrade to version 9.2.10 or 10.0.5, which fixes the issue.

Improper Access Control vulnerability in Apache Traffic Server. This issue affects Apache Traffic Server: from 9.2.0 through 9.2.8, from 10.0.0 through 10.0.3. Users are recommended to upgrade to version 9.2.9 or 10.0.4, which fixes the issue.

Expected Behavior Violation vulnerability in Apache Traffic Server. This issue affects Apache Traffic Server: from 9.0.0 through 9.2.8, from 10.0.0 through 10.0.3. Users are recommended to upgrade to versions 9.2.9 or 10.0.4 or newer, which fixes the issue.

Improper Input Validation vulnerability in Apache Traffic Server. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.8, from 10.0.0 through 10.0.3. Users are recommended to upgrade to version 9.2.9 or 10.0.4, which fixes the issue.

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

Unspecified vulnerability in the HTTP/2 experimental feature in Apache Traffic Server 5.3.x before 5.3.2 has unknown impact and attack vectors, a different vulnerability than CVE-2015-5206.

The HTTP/2 experimental feature in Apache Traffic Server 5.3.x before 5.3.1 allows remote attackers to cause a denial of service (out-of-bounds access and daemon crash) or possibly execute arbitrary code via vectors related to the (1) frame_handlers array or (2) set_dynamic_table_size function.

Unspecified vulnerability in the HTTP/2 experimental feature in Apache Traffic Server before 5.3.x before 5.3.2 has unknown impact and attack vectors, a different vulnerability than CVE-2015-5168.

Apache Traffic Server 5.1.x before 5.1.1 allows remote attackers to bypass access restrictions by leveraging failure to properly tunnel remap requests using CONNECT.

Apache Traffic Server before 6.2.1 generates a coredump when there is a mismatch between content length and chunked encoding.

Improper Input Validation vulnerability for the xdebug plugin in Apache Software Foundation Apache Traffic Server can lead to cross site scripting and cache poisoning attacks.This issue affects Apache Traffic Server: 9.0.0 to 9.1.3. Users should upgrade to 9.1.4 or later versions.

Improper Check for Unusual or Exceptional Conditions vulnerability in handling the requests to Apache Traffic Server. This issue affects Apache Traffic Server 8.0.0 to 9.1.2.

Improper Check for Unusual or Exceptional Conditions vulnerability handling requests in Apache Traffic Server allows an attacker to crash the server under certain conditions. This issue affects Apache Traffic Server: from 8.0.0 through 9.1.3.

Unspecified vulnerability in Apache Traffic Server 3.x through 3.2.5, 4.x before 4.2.1.1, and 5.x before 5.0.1 has unknown impact and attack vectors, possibly related to health checks.

Apache Traffic Server before 5.1.2 allows remote attackers to cause a denial of service via unspecified vectors, related to internal buffer sizing.

Apache Traffic Server 2.0.x and 3.0.x before 3.0.4 and 3.1.x before 3.1.3 does not properly allocate heap memory, which allows remote attackers to cause a denial of service (daemon crash) via a long HTTP Host header.

Apache Traffic Server before 2.0.1, and 2.1.x before 2.1.2-unstable, does not properly choose DNS source ports and transaction IDs, and does not properly use DNS query fields to validate responses, which makes it easier for man-in-the-middle attackers to poison the internal DNS cache via a crafted response.

Improper Input Validation vulnerability in Apache Software Foundation Apache Traffic Server.This issue affects Apache Traffic Server: through 9.2.1.

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Apache Software Foundation Apache Traffic Server.This issue affects Apache Traffic Server: from 8.0.0 through 9.2.0. 8.x users should upgrade to 8.1.7 or later versions 9.x users should upgrade to 9.2.1 or later versions

Improper Input Validation vulnerability in Apache Software Foundation Apache Traffic Server.  The configuration option proxy.config.http.push_method_enabled didn't function.  However, by default the PUSH method is blocked in the ip_allow configuration file.This issue affects Apache Traffic Server: from 8.0.0 through 9.2.0. 8.x users should upgrade to 8.1.7 or later versions 9.x users should upgrade to 9.2.1 or later versions

Improper input validation vulnerability on the range header in Apache Software Foundation Apache Traffic Server.This issue affects Apache Traffic Server: through 9.2.1.

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Apache Software Foundation Apache Traffic Server.This issue affects Apache Traffic Server: 8.0.0 to 9.2.0.

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 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 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.