What’s Vulnerable › Vulnerabilities
CVE-2023-37464: Incorrect Authentication Tag length usage in AES GCM decryption in OpenIDC/cjose
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.7% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2023-07-14 · updated 2026-06-17
- Weakness: CWE-327
Description
OpenIDC/cjose is a C library implementing the Javascript Object Signing and Encryption (JOSE). The AES GCM decryption routine incorrectly uses the Tag length from the actual Authentication Tag provided in the JWE. The spec says that a fixed length of 16 octets must be applied. Therefore this bug allows an attacker to provide a truncated Authentication Tag and to modify the JWE accordingly. Users should upgrade to a version >= 0.6.2.2. Users unable to upgrade should avoid using AES GCM encryption and replace it with another encryption algorithm (e.g. AES CBC).
Affected products
- OpenIDC cjose: before 0.6.2.2 — fixed in 0.6.2.2
How to fix
Upgrade to a fixed version: OpenIDC cjose 0.6.2.2. Check the vendor advisory for mitigations.
References
- https://datatracker.ietf.org/doc/html/rfc7518#section-4.7
- https://github.com/OpenIDC/cjose/commit/7325e9a5e71e2fc0e350487ecac7d84acdf0ed5e
- https://github.com/OpenIDC/cjose/releases/tag/v0.6.2.2
- https://github.com/OpenIDC/cjose/security/advisories/GHSA-3rhg-3gf2-6xgj
- https://lists.debian.org/debian-lts-announce/2023/08/msg00002.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DFWAPMYYVBO2U65HPYDTBEKNSXG4TP5C/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LCQJXKDPCWCXB2V4JMQ3UWYJ4UIBPUW6/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PTZHOVGY7AHGNMEY245HK4Q36AMA53AL/
- https://www.debian.org/security/2023/dsa-5472
- https://datatracker.ietf.org/doc/html/rfc7518#section-4.7
- https://github.com/OpenIDC/cjose/commit/7325e9a5e71e2fc0e350487ecac7d84acdf0ed5e
- https://github.com/OpenIDC/cjose/releases/tag/v0.6.2.2
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