Granian: DoS via WSGI response header panic
Priority MEDIUM 60CWE-248Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-248.
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0027 19th percentileScored 2026-11-07
Fix Fixed granian (emmett-framework): 2.7.4granian (PyPI): 2.7.4
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| emmett-framework | granian | 0.2.0 to before 2.7.4 | 2.7.4 | Patch available | CNA |
| — | granian (PyPI) | 0.2.0 to before 2.7.4 | 2.7.4 | Patch available | GHSA-f5p7-9fr5-8jmj |
- granian Vendoremmett-framework Affected 0.2.0 to before 2.7.4 Fixed in 2.7.4 Patch available CNA
- granian (PyPI) Vendor— Affected 0.2.0 to before 2.7.4 Fixed in 2.7.4 Patch available GHSA-f5p7-9fr5-8jmj
Remediation
- Fix · CNA granian (emmett-framework) Fixed in 2.7.4
- Fix · GHSA-f5p7-9fr5-8jmj granian (PyPI) Fixed in 2.7.4 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-42545
- 2026-10-03 Alias added: GHSA-f5p7-9fr5-8jmj
References
More emmett-framework vulnerabilities
- TI-2026-30824 Granian: Unauthenticated DoS via WebSocket subprotocol header panic CVSS 3.1HIGH 7.5
- TI-2026-20684 Emmett has an Unhandled CookieError Exception Causing Denial of Service CVSS 3.1HIGH 7.5
Sources
- CVE-2026-42545 · CVE Program
- CVE-2026-42545 · NVD
- FIRST EPSS
- GHSA-f5p7-9fr5-8jmj · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences