CVE-2026-115877

MEDIUM

MEDIUM Priority: 0.01 BB Relevance: 61/100

Published: 2026-10-23 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network No Auth No Interaction Scope Change

CVSS Vector Breakdown

AV: Network

AC: High

PR: None

UI: None

S: Changed

C: Low

I: Low

A: None

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.