CVE-2025-55702
Apache Traffic Server: An unread Expect: 100-continue request body is framed as a new request
- State
- Published
- Severity
- 7.0 High
- Published
- Oct 21, 2026
- Updated
- Oct 23, 2026
- Reserved
- Aug 13, 2025
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 7.0 High | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N | apache |
| 3.1 | 8.7 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N | apache |
Weaknesses
- CWE-444 Inconsistent Interpretation of HTTP Requests
Affected Products
| Product | Versions |
|---|---|
Apache Traffic ServerApache Software Foundation |
|
References
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.