CVE-2026-33996
LibJWT has NULL/bounds validation in JWK octet and RSA PSS parsing
- State
- Published
- Severity
- 5.8 Medium
- Published
- Mar 27, 2026
- Updated
- Mar 31, 2026
- Reserved
- Mar 24, 2026
Description
LibJWT is a C JSON Web Token Library. Starting in version 3.0.0 and prior to version 3.3.0, the JWK parsing for RSA-PSS did not protect against a NULL value when expecting to parse JSON string values. A specially crafted JWK file could exploit this behavior by using integers in places where the code expected a string. This was fixed in v3.3.0. A workaround is available. Users importing keys through a JWK file should not do so from untrusted sources. Use the `jwk2key` tool to check for validity of a JWK file. Likewise, if possible, do not use JWK files with RSA-PSS keys.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.8 Medium | CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:A/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L | GitHub_M |
Weaknesses
- CWE-476 NULL Pointer Dereference
Affected Products
| Product | Versions |
|---|---|
libjwtbenmcollins |
|
References
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.