In the Bouncy Castle JCE Provider version 1.55 and earlier ECDSA 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 bc-javaup to 1.55 inclusive
• debian debian linux8.0

Package-level exposure

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

Other highest-scoring records for the same primary product.

• CVE-2007-6721The Legion of the Bouncy Castle Java Cryptography API before release 1.38, as used in Crypto Provider Package before 1.36, has unknown impac
  41Plan
• CVE-2018-1000613Legion of the Bouncy Castle Legion of the Bouncy Castle Java Cryptography APIs 1.58 up to but not including 1.60 contains a CWE-470: Use of
  40Plan
• CVE-2026-58062Stapled OCSP response accepted without binding to the checked certificate
  37Monitor
• CVE-2026-8763Name Constraints bypass via trailing dot in rfc822Name and URI
  37Monitor
• CVE-2026-59650MTI/A0 DH agreement exponentiates unvalidated peer value
  37Monitor
• CVE-2026-59638JSSE hostname verifier CN-fallback enabled by default despite documented opt-in
  37Monitor

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.