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Fencer Vulns
medium 5.9

CVE-2026-42545 json

Granian: DoS via WSGI response header panic

published 2026-05-06 6 mo ago modified 2026-10-26 13 d 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

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

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

Weakness
  • CWE-248 Uncaught Exception
  • CWE-755 Improper Handling of Exceptional Conditions

References

Sources

Fencer Vulns 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.