CVE-2026-115877Twisted: HTTP Request Smuggling in twisted.web via a Bare CR or LF in a Header Value
- 5.4MediumCVSS base score
- 0.26%Exploitation in 30 daysEPSS · top 83% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- https://github.com/twisted/twisted/security/advisories/GHSA-q7qq-6mhp-9rc4 (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
Published
- 6 days later
· 6 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N |
| NVDNVD · Awaiting Analysis | 3.1 | Medium5.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.26% · top 83% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.4.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPITwistedGHSA-q7qq-6mhp-9rc4 (opens in a new tab)
References
References5
- https://github.com/twisted/twisted/security/advisories/GHSA-q7qq-6mhp-9rc4 (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/twisted/twisted/pull/12755 (opens in a new tab)x_refsource_MISC
- https://github.com/twisted/twisted/commit/022b6f7feb5980166c71f54e2c0d8f4f21ff6e1a (opens in a new tab)x_refsource_MISC
- https://github.com/twisted/twisted/commit/1616f702d36eda8990a5a5b22ad70fab140a7eb1 (opens in a new tab)x_refsource_MISC
- https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-109153 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-q7qq-6mhp-9rc4 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-115877)Record last updated .