medium4.4
CVE-2026-102270
PyJWT: ReDoS vulnerability when calling the `is_pem_format` function.
Impact
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT is_pem_format is affected because lazy PEM regular expression backtracks extensively. This occurs when a certificate-like input contains repeated BEGIN markers without a matching END marker. As a result, is_pem_format performs unbounded backtracking while searching for a PEM end marker. Consequently, an attacker can cause intensive CPU consumption. This issue is fixed in version 2.14.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pyjwt | <= 2.13.0 | 2.14.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Pyjwt Project | Pyjwt | before 2.14.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-jwrc-g2q2-pq5p
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jwrc-g2q2-pq5p
- https://nvd.nist.gov/vuln/detail/CVE-2026-102270
- https://github.com/jpadilla/pyjwt/commit/8b4e233a22206b34ec1186e912e75c0b2396ac07
- https://github.com/jpadilla/pyjwt/releases/tag/2.14.0