Twisted: HTTP Request Smuggling in twisted.web via a Bare CR or LF in a Header Value

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-115877
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-23 21:17:23 UTC
Updated2026-10-23 21:17:23 UTC
DescriptionTwisted 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.

Risk And Classification

Primary CVSS: v3.1 5.4 MEDIUM from [email protected]

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

Problem Types: CWE-444 | CWE-444 CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.4MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
3.1CNADECLARED5.4MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Twisted Twisted affected < 26.10.0rc1 Not specified

References

ReferenceSourceLinkTags
github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1 [email protected] github.com
github.com/twisted/twisted/commit/022b6f7feb5980166c71f54e2c0d8f4f21ff6e1a [email protected] github.com
github.com/twisted/twisted/commit/1616f702d36eda8990a5a5b22ad70fab140a7eb1 [email protected] github.com
github.com/twisted/twisted/security/advisories/GHSA-q7qq-6mhp-9rc4 [email protected] github.com
github.com/twisted/twisted/pull/12755 [email protected] github.com
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