Insufficient Verification of Data Authenticity Affecting joserfc package, versions <1.7.2-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.11% (2nd percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-JOSERFC-18392579
  • published30 Jul 2026
  • disclosed29 Jul 2026

Introduced: 29 Jul 2026

NewCVE-2026-62995  (opens in a new tab)
CWE-345  (opens in a new tab)

How to fix?

Upgrade Debian:unstable joserfc to version 1.7.2-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream joserfc package and not the joserfc package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1