CVE-2026-44699

Published: Mag 15, 2026 Last Modified: Mag 18, 2026
ExploitDB:
Other exploit source:
Google Dorks:
CRITICAL 9,1
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Confidentiality: N/A
Integrity: N/A
Availability: N/A

Description

AI Translation Available

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.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0004
Percentile
0,1th
Updated

EPSS Score Trend (Last 5 Days)

327

Use of a Broken or Risky Cryptographic Algorithm

Draft
Abstraction: Class Structure: Simple
Common Consequences
Security Scopes Affected:
Confidentiality Integrity Accountability Non-Repudiation
Potential Impacts:
Read Application Data Modify Application Data Hide Activities
Applicable Platforms
Languages: Not Language-Specific, Verilog, VHDL
Technologies: Not Technology-Specific, ICS/OT
Likelihood of Exploit: High
View CWE Details
347

Improper Verification of Cryptographic Signature

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control Integrity Confidentiality
Potential Impacts:
Gain Privileges Or Assume Identity Modify Application Data Execute Unauthorized Code Or Commands
Applicable Platforms
All platforms may be affected
View CWE Details
https://github.com/benmcollins/libjwt/security/advisories/G…
https://github.com/benmcollins/libjwt/security/advisories/GHSA-q843-6q5f-w55g
https://github.com/benmcollins/libjwt/security/advisories/G…
https://github.com/benmcollins/libjwt/security/advisories/GHSA-q843-6q5f-w55g