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2 vulnerabilities by benmcollins

CVE-2026-44699 (GCVE-0-2026-44699)

Vulnerability from cvelistv5 – Published: 2026-05-15 16:08 – Updated: 2026-05-15 18:04
VLAI
Title
LibJWT: Algorithm confusion allows JWT forgery with RSA JWK as empty-key HMAC
Summary
LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid JWT without knowing any secret or RSA private key. This is an algorithm-confusion authentication bypass. It affects applications that load RSA keys from JWKS where alg is omitted, which is valid JWK syntax and common in real deployments, and then choose the verification algorithm from the JWT header, for example in a kid lookup callback. This vulnerability is fixed in 3.3.3.
Severity
9.1 (Critical)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CWE
  • CWE-327 - Use of a Broken or Risky Cryptographic Algorithm
  • CWE-347 - Improper Verification of Cryptographic Signature
Assigner
References
Impacted products
Vendor Product Version
benmcollins libjwt Affected: >= 3.0.0, < 3.3.3
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CVE-2026-33996 (GCVE-0-2026-33996)

Vulnerability from cvelistv5 – Published: 2026-03-27 22:21 – Updated: 2026-03-31 18:53
VLAI
Title
LibJWT has NULL/bounds validation in JWK octet and RSA PSS parsing
Summary
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.
Severity
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
CWE
  • CWE-476 - NULL Pointer Dereference
Assigner
References
Impacted products
Vendor Product Version
benmcollins libjwt Affected: >= 3.0.0, < 3.3.0
Create a notification for this product.
Show details on NVD website
To clipboard 

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