CVE-2025-31699

High

Description

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.

SeverityHigh
CVSS8.9
Exploit probability—
ProductApache Traffic Server
PublishedOct 21, 2026
First seenOct 21, 2026
Weakness typeCWE-444CWE-444

How to fix

Affected products

ProductAffected versionsFixed in
Apache Software Foundation Apache Traffic Server8.0.0 ≤ v ≤ 8.1.11, 9.0.0 ≤ v ≤ 9.2.15, 10.0.0 ≤ v ≤ 10.1.4, 10.2.0—

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