CVE-2026-115877
Twisted: HTTP Request Smuggling in twisted.web via a Bare CR or LF in a Header Value
- State
- Published
- Severity
- 5.4 Medium
- Published
- Oct 23, 2026
- Updated
- Oct 29, 2026
- Reserved
- Oct 23, 2026
Description
Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.web.http.HTTPChannel.headerReceived rejects a NUL byte in an HTTP header value but accepts a bare carriage return or bare line feed. Because Twisted splits header lines only on CRLF, a hidden Content-Length header can remain folded into another value while a lenient front end treats the bare character as a line terminator. The resulting framing disagreement can smuggle a following request past front-end access controls, poison a shared connection or cache, and expose a later client to the wrong response. This issue is an incomplete-fix residual of earlier Twisted request-smuggling protections. This issue is fixed in version 26.10.0rc1.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.4 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N | GitHub_M |
Weaknesses
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Products
| Product | Versions |
|---|---|
twistedtwisted |
|
References
- https://github.com/twisted/twisted/security/advisories/GHSA-q7qq-6mhp-9rc4
- https://github.com/twisted/twisted/pull/12755
- https://github.com/twisted/twisted/commit/022b6f7feb5980166c71f54e2c0d8f4f21ff6e1a
- https://github.com/twisted/twisted/commit/1616f702d36eda8990a5a5b22ad70fab140a7eb1
- https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1
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.