fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKe…
Exact source revision recorded 30 Oct 2026 01:54:28 UTC. It does not establish the source's current position. Latest evidence.
euvd · EUVD-2026-95344
Publishedfast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKeyOrSecret, allowedAlgorithms remains active, hasKey is false, and the empty signature avoids the verifySignature gate. An attacker can therefore submit a token containing arbitrary claims without possessing a signing key, resulting in authentication or authorization bypass. Claim validators still run, and non-empty keys, an empty key without algorithms, and the async key resolver path do not have this behavior. This issue is fixed in version 6.3.1.
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Oct 8, 2026, 9:44:06 PM
dateUpdated: Oct 9, 2026, 2:32:14 PM
- Source published
- Oct 8, 2026, 9:44:06 PM (timezone not stated)
- Source modified
- Oct 9, 2026, 2:32:14 PM (timezone not stated)
- Observed here
- 30 Oct 2026 01:54:28 UTC
- Source terms
- ENISA EUVD · source terms and attribution apply
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EUVD CVSS 3.1 · 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N