Answer in brief
CVE-2026-107721 records a Medium severity (CVSS 5.9) vulnerability in fast-jwt clockTolerance: Infinity silently bypasses both exp and nbf validation (and persists in the verifier cache). The current sources do not mark it as known exploited. The current feed maps nearform/fast-jwt (generic), fast-jwt (npm), fast-jwt (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps nearform/fast-jwt (generic), fast-jwt (npm), fast-jwt (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| nearform/fast-jwtgeneric | <6.3.0 | 6.3.0 |
| fast-jwtnpm | <=6.2.4 | 6.3.0 |
| fast-jwtnpm | >=0 <6.3.0 | 6.3.0 |
Published upstream
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 8, 2026
fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.0, fast-jwt createVerifier accepts Infinity for clockTolerance because its option validation checks type and negativity but not finiteness. In validateClaimDateValue, infinite positive and negative modifiers make exp and nbf comparisons always pass, allowing expired or not-yet-active tokens to be accepted. The verifier cache also derives infinite bounds, so entries created under this configuration can remain valid until eviction. Exploitation requires an application administrator or equivalent configuration path to set clockTolerance to Infinity. This issue is fixed in version 6.3.0.
Quoted source text, attributed separately from HOL analysis.