In Bouncy Castle JCE Provider version 1.55 and earlier the DSA does not fully validate ASN.1 encoding of signature on verification.

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• bouncycastle legion-of-the-bouncy-castle-java-crytography-api1.38 and later · before 1.56
• canonical ubuntu linux14.04
• netapp 7-mode transition toolall versions
• redhat satellite6.4
• redhat satellite capsule6.4

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

The verifier takes the algorithm to verify with from the token’s own header. Untrusted data ends up deciding its own verification rule.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1const claims = jwt.verify(token, publicKey);

1const claims = jwt.verify(token, publicKey, {2  algorithms: ["RS256"],3  issuer: "https://id.example.com",4  audience: "portal",5});

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.