Improper Verification of Cryptographic Signature Affecting jose2 package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PUB-JOSE2-15869634
- published1 Apr 2026
- disclosed31 Mar 2026
- creditUnknown
Introduced: 31 Mar 2026
NewCVE-2026-34240 (opens in a new tab)How to fix?
There is no fixed version for jose2.
Overview
Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature via the jwk header parameter during the signature verification. An attacker can bypass signature verification by embedding an attacker-controlled public key in the header and signing the token with the corresponding private key, allowing the creation of forged tokens that are accepted as valid.
Workaround
This vulnerability can be mitigated by rejecting tokens where the jwk header is present unless that key matches a key already present in the application's trusted key store.