Apache Traffic Server: Origin connection still owed a request body is reused, enabling request smuggling

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

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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.

Source published

21 Oct 2026 18:22:28 UTC

Source modified

23 Oct 2026 11:06:22 UTC

Observed here

23 Oct 2026 16:01:20 UTC

Source terms

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CVSS 3.1 · 8.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L

CVSS 4.0 · 9.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:L/SC:H/SI:H/SA:L