Cadwyn is vulnerable to an XSS attack through its docs page
Priority HIGH 66CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- High · Low · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.
Summary
Cadwyn creates production-ready community-driven modern Stripe-like API versioning in FastAPI. In versions before 5.4.3, the version parameter of the "/docs" endpoint is vulnerable to a Reflected XSS (Cross-Site Scripting) attack. This XSS would notably allow an attacker to execute JavaScript code on a user's session for any application based on Cadwyn via a one-click attack. The vulnerability has been fixed in version 5.4.3.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00278 20th percentileScored 2026-11-07
Fix Fixed cadwyn (zmievsa): 5.4.3cadwyn (PyPI): 5.4.3
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 |
|---|---|---|---|---|---|
| zmievsa | cadwyn | before 5.4.3 | 5.4.3 | Patch available | CNA |
| — | cadwyn (PyPI) | before 5.4.3 | 5.4.3 | Patch available | GHSA-2gxp-6r36-m97r |
- cadwyn Vendorzmievsa Affected before 5.4.3 Fixed in 5.4.3 Patch available CNA
- cadwyn (PyPI) Vendor— Affected before 5.4.3 Fixed in 5.4.3 Patch available GHSA-2gxp-6r36-m97r
Remediation
- Fix · CNA cadwyn (zmievsa) Fixed in 5.4.3
- Fix · GHSA-2gxp-6r36-m97r cadwyn (PyPI) Fixed in 5.4.3 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2025-53528
- 2026-10-03 Alias added: GHSA-2gxp-6r36-m97r
References
Other 5
- https://github.com/zmievsa/cadwyn/security/advisories/GHSA-2gxp-6r36-m97r
- https://github.com/zmievsa/cadwyn/commit/b424ecd57cd8dabbc8fe39b8f8ccafea629c7728
- https://github.com/pypa/advisory-database/tree/main/vulns/cadwyn/PYSEC-2025-71.yaml
- https://github.com/zmievsa/cadwyn
- https://github.com/zmievsa/cadwyn/blob/5.4.3/CHANGELOG.md#543
Sources
- CVE-2025-53528 · CVE Program
- CVE-2025-53528 · NVD
- FIRST EPSS
- GHSA-2gxp-6r36-m97r · GitHub Advisory Database · CC BY 4.0
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