CVE-2026-62995
joserfc accepts JWT with padding, leading to JWT malleability
En bref
- Source
- NVD
- EPSS
- EPSS 0.14 % · centile 4 ()
- État
- PUBLISHED
- Publiée
- Mise à jour
- Attribuée par
- GitHub_M
- Statut NVD
- Deferred
Description
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. in versions 1.7.1 and prior, joserfc accepts JWTs with trailing padding (==) which are not conforming to the JOSE specifications. This leads to malleability of the JWTs when consumed by joserfc. Depending on this application this might or not be an issue. This could lead to bypass of token revocation or anti-replay protection when implemented as a deny list of tokens or a deny list of token hashes. Note that ECDSA JWS are always malleable because of the malleability of ECDSA signatures (first test case in the code bellow). This makes a scheme which assumes that JWTs are not malleable brittle. However for other signatures (or MAC) schemes it might make sense to assume non malleability of the token. This issue has been fixed in version 1.7.2.
Faiblesses (CWE)
- CWE-345 — Vérification insuffisante de l'authenticité des données
Références
Scores
| Version | Score | Vecteur | Évalué par |
|---|---|---|---|
| CVSS 4.0 | LOW 2.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | GitHub_M |
| CVSS 4.0 | LOW 2.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · security-advisories@github.com (Secondary) |
Références européennes
- ENISA EUVD · EUVD-2026-50450
- GCVE · GCVE-0-2026-62995
Produits affectés
| Produit | Versions |
|---|---|
| authlib · joserfc | affected < 1.7.2 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |