Apache Traffic Server: A malformed 302 response bypasses parse-error rejection through the Transfer-Encoding: chunked carve-out

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Apache Traffic Server forwarded a malformed 302 response that should have been rejected as a parse error, because the Transfer-Encoding: chunked carve-out bypassed the rejection path. A response that two peers can read differently is then stored and served, allowing cache poisoning and response-framing desync. 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.

Source published

21 Oct 2026 18:26:32 UTC

Source modified

23 Oct 2026 21:22:57 UTC

Observed here

23 Oct 2026 22:48:20 UTC

Source terms

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CVSS 3.1 · 9.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N

CVSS 4.0 · 9.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:L/SI:H/SA:N