CVE-2025-31699
HighCVSS 8.9Exploitation Probability (EPSS)
Low risk28th percentile - higher than 28% of all known CVEs
Summary
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.
Risk Assessment
The flaw enables bypassing access controls, disrupting other users' traffic, and cache poisoning. This can lead to unauthorized access to resources and distribution of false content.
Recommendation
Upgrade Apache Traffic Server to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue. Verify that vulnerable versions in ranges 8.0.0–8.1.11, 9.0.0–9.2.15, 10.0.0–10.1.4, and 10.2.0 are not in use.
Other vulnerabilities in Apache Traffic Server
See all- CVE-2017-5659High
Apache Traffic Server before 6.2.1 generates a coredump when there is a mismatch between content length and chunked encoding.
- CVE-2016-5396High
Apache Traffic Server versions 6.0.0 to 6.2.0 are affected by an HPACK Bomb Attack.
- CVE-2014-3525High
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.
- CVE-2026-111815Critical
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.
- CVE-2026-111814Critical
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.
- CVE-2026-111812Critical
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.
- CVE-2026-111811Critical
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.
- CVE-2026-111809Critical
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.
- CVE-2026-111816Critical
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.
- CVE-2026-111813Critical
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.
Original NVD description (English source)
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, which lets an attacker smuggle requests past ATS access controls, disrupt other users' requests, or poison the cache. 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, 10.2.0. Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS