CVE-2026-62995

Published: Lug 29, 2026 Last Modified: Lug 29, 2026
ExploitDB:
Other exploit source:
Google Dorks:
LOW 2,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: low
User Interaction: none
Confidentiality: N/A
Integrity: N/A
Availability: N/A

Description

AI Translation Available

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.

345

Insufficient Verification of Data Authenticity

Draft
Abstraction: Class Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Other
Potential Impacts:
Varies By Context Unexpected State
Applicable Platforms
Technologies: ICS/OT
View CWE Details
https://github.com/authlib/joserfc/security/advisories/GHSA…
https://github.com/authlib/joserfc/security/advisories/GHSA-5jhw-7jv7-qcqq