CVE-2025-55702
When a client sends a POST with Expect: 100-continue and the origin answers before reading the…
- Risk score
- 60/100
- CVSS
- 8.7 v3.1
- Exploit chance (30 days)
- 0.3%
- Published
- 21 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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 f…
- Affected
- See advisory
- Fix
- Upgrade the product to 9.2.16, 10.1.5 or 10.2.1 (whichever matches your release line), or later.
- Exploitation
- No known exploitation
Why it is Amber
- CVSS 8.7 high
- Remotely exploitable without logging in
References
Original description
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. 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.
Last activity 21 Oct 2026. Patch Forecast updates every hour.