CVE-2026-42545 json
Granian: DoS via WSGI response header panic
published 6mo ago modified 14d ago also GHSA-f5p7-9fr5-8jmj , PYSEC-2026-2502 , EUVD-2026-29856
- cvss
- 5.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 19%
- public exploits
- 0
- none known
Summary
Granian is a Rust HTTP server for Python applications. From 0.2.0 to 2.7.4, Granian aborts a worker process if a WSGI application returns an invalid HTTP response header name or value. The WSGI response conversion path uses .unwrap() on both the header name and header value constructors, so malformed output from the application becomes a process abort instead of a handled error. This vulnerability is fixed in 2.7.4.
Patch / fix
- pypi granian 2.7.4
Is CVE-2026-42545 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5mo ago
Exploit prediction
0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- github.com https://github.com/emmett-framework/granian/security/advisories/GHSA-f5p7-9fr5-8jmj referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| OSV | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| GitHub | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | granian | >=0.2.0, <2.7.4 |
2.7.4 |
Affected products
- emmett-framework granian
Classification
References
Sources
- CVE List CVE-2026-42545
- GitHub Advisory GHSA-f5p7-9fr5-8jmj
- NVD CVE-2026-42545
- OSV PYSEC-2026-2502
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.