Apache Traffic Server vulnerabilities

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

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

Unspecified vulnerability in Apache Traffic Server versions 3.x through 3.2.5, 4.x before 4.2.1.1, and 5.x before 5.0.1. This vulnerability may be related to health checks, but its impact and attack vectors are unknown.

Apache Traffic Server can resume a TLS session across SNI virtual hosts without re-verifying a client certificate required by the resumed host's verify_client STRICT policy. This affects versions 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0.

Apache Traffic Server's default outbound session-sharing policy can reuse a pooled TLS session authenticated with one client certificate for a transaction configured to present a different one. This affects versions 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0.

Apache Traffic Server's origin_server_auth plugin lets a client force signing of attacker-chosen AWS request headers under the proxy's own credentials. Affects versions 8.0.0–8.1.11, 9.0.0–9.2.15, 10.0.0–10.1.4, and 10.2.0.

Apache Traffic Server's experimental tsmemcache plugin allows unauthenticated network read, write, and deletion of the shared proxy cache. Affects versions 8.0.0–8.1.11, 9.0.0–9.2.15, 10.0.0–10.1.4, and 10.2.0.

Apache Traffic Server allows request smuggling via HEAD requests that carry Content-Length or Transfer-Encoding headers. This affects versions 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0.

Apache Traffic Server forwards malformed 302 responses that should be rejected as parse errors because the Transfer-Encoding: chunked carve-out bypasses the rejection path. A response that two peers can read differently is stored and served, allowing cache poisoning and response-framing desync.

Apache Traffic Server's experimental magick plugin lets an unauthenticated client control ImageMagick convert arguments in its default (unsigned) configuration. Affects versions 8.0.1–8.1.11, 9.0.0–9.2.15, 10.0.0–10.1.4, and 10.2.0.

Apache Traffic Server contains an improper access control vulnerability. This issue affects Apache Traffic Server from 9.0.0 through 9.2.14 and from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fixes the issue. This CVE supersedes CVE-2026-41920, whose record listed the affected 9.x versions as 9.0.0 through 9.1.14 and the fixed version as 9.1.15; all 9.2.x releases before 9.2.15 are affected.

The Apache Traffic Server certifier plugin generates certificates based on attacker-controlled client SNI. This issue affects Apache Traffic Server versions from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, and from 10.0.0 through 10.1.3.

Apache Traffic Server truncates over-long header names, allowing header aliasing, request smuggling, and policy bypass. This issue affects versions 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3.

Apache Traffic Server does not reject Transfer-Encoding in HTTP/2 requests, allowing downgrade request smuggling. This issue affects versions 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3.

Apache Traffic Server allows request smuggling when chunked messages are malformed. This issue affects versions 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3.

Apache Traffic Server has an Improper Access Control vulnerability. This affects versions from 9.0.0 to 9.1.14 and from 10.0.0 to 10.1.3.

Apache Traffic Server has an Improper Input Validation vulnerability. This affects versions from 9.2.0 to 9.2.14 and from 10.1.0 to 10.1.3.

Improper Input Validation vulnerability in Apache Traffic Server. This issue affects Apache Traffic Server through version 9.2.1.

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 frame_handlers array or set_dynamic_table_size function.

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.

An unspecified vulnerability in the HTTP/2 experimental feature in Apache Traffic Server before version 5.3.2 may lead to unknown impact and attack vectors.

Apache Traffic Server can crash with a null pointer dereference when a client POST request is torn down via half-close while a chunked origin response is being reparsed from a reentrant write-ready callback, a timing-dependent race introduced by the CVE-2021-32564 flow-control backports. This issue affects Apache Traffic Server: 9.2.15, 10.1.4, 10.2.0.

Apache Traffic Server can stall a chunked transfer that it passes through with its trailers removed (proxy.config.http.drop_chunked_trailers) until the connection times out, because it waits for the trailer bytes it has already dropped. Trailer dropping is on by default in 10.x. In 8.1.11 and 9.2.x it is off by default, and those versions are affected only if it is enabled. This issue affects Apache Traffic Server: 8.1.11, from 9.2.5 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0.

Apache Traffic Server 9.2.15, 10.1.4 and 10.2.0 write one unthrottled diagnostic log line for every internal @ header they strip, so a request carrying many such headers makes the proxy write far more log data than the request contains.

Apache Traffic Server can be used to exhaust an HTTP/1.1 origin's worker pool via a malformed padded HTTP/2 DATA frame. This issue affects Apache Traffic Server from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, and 10.2.0. Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.

Apache Traffic Server can be used to exhaust an HTTP/1.1 origin's worker pool via a truncated HTTP/2 Content-Length value. This issue affects versions 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0.

Apache Traffic Server's experimental wasm plugin has a use-after-free in its transaction-close handler and forwards unvalidated guest-supplied metric IDs to the internal stats API. This affects versions 10.0.0 through 10.1.4 and 10.2.0.

When a client sends a POST with Expect: 100-continue and the origin answers before reading the body, Apache Traffic Server parses the unread body left on the client connection as the next request. An attacker behind a front-end proxy that shares connections to Traffic Server can use this to smuggle requests past the front end and desynchronize responses for other users.

Apache Traffic Server can return an origin connection to the shared pool while the origin is still waiting on a request body the client declared but never fully sent, including when the client used Expect: 100-continue. The origin then reads a later request on that connection as leftover body data, allowing an attacker to smuggle requests past ATS access controls, disrupt other users' requests, or poison the cache.

Apache Traffic Server updates the HTTP/2 HPACK dynamic table before confirming the header block encoded successfully, so an encode failure leaves the encoder out of sync with the peer decoder and corrupts subsequent header blocks on the connection. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3.

Apache Traffic Server allows redirect-limit bypass when plugins reset the retry counter, enabling SSRF amplification. This affects versions from 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3. Users are recommended to upgrade to 9.2.15 or 10.1.4.

Several Apache Traffic Server experimental plugins have memory-safety and limit-bypass errors. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

The Apache Traffic Server multiplexer plugin overruns its chunk-decode buffer on upstream input, enabling denial of service. This issue affects Apache Traffic Server from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

The Apache Traffic Server webp_transform plugin can decode unsafely and serve mislabeled, cacheable responses. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

The Apache Traffic Server intercept plugin has a use-after-free. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3.

The header_rewrite plugin in Apache Traffic Server can crash or corrupt memory during cookie operations and CIDR condition matching. This affects versions from 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3. Users are recommended to upgrade to 9.2.15 or 10.1.4.

The Apache Traffic Server prefetch plugin can crash when processing attacker-influenced input. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3.

The Apache Traffic Server ts_lua plugin mishandles initialization, transform context, and per-instance state. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

The Apache Traffic Server uri_signing and url_sig plugins can exhaust the stack or crash on attacker input. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

The Apache Traffic Server txn_box plugin overflows the stack from attacker-controlled input. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

The regex_remap plugin in Apache Traffic Server overflows the stack and integers from substitution input. This affects versions from 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3. Users are recommended to upgrade to 9.2.15 or 10.1.4.

The Apache Traffic Server ESI plugin can recurse without bound and fetch attacker-controlled URLs. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

The Cripts framework of Apache Traffic Server has out-of-bounds writes, path traversal, and use-after-free errors. Affected versions: 10.0.0 through 10.1.3.

Apache Traffic Server leaks memory when handling HostDB SRV records. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

Apache Traffic Server has use-after-free and time-of-check/time-of-use errors in remap configuration handling. This affects versions from 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3. Users are recommended to upgrade to 9.2.15 or 10.1.4.

Apache Traffic Server mishandles on-disk cache fields and object lifetimes, corrupting state or crashing. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

Apache Traffic Server can crash from null dereferences and dangling references in TLS and SNI handling. This affects versions from 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3. Users are recommended to upgrade to 9.2.15 or 10.1.4.

Apache Traffic Server reads out of bounds while parsing DNS answers. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3.

Apache Traffic Server can bypass IP access controls on UDS listeners and through ACL matching errors. This affects versions from 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3. Users are recommended to upgrade to 9.2.15 or 10.1.4.

Apache Traffic Server mishandles PROXY protocol input, truncating ports and overflowing the stack. Affects versions from 8.0.0 through 8.1.11, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3.