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TI-2026-69685 Aliases CVE-2026-107721GHSA-687g-22h4-j4w4

fast-jwt clockTolerance Infinity bypasses exp and nbf checks

Priority LOW 28CWE-613Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
None
Attack complexity
High
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-613.

Summary

fast-jwt createVerifier accepts Infinity as clockTolerance because option validation checks type and sign but not finiteness. In validateClaimDateValue, infinite modifiers make the exp and nbf comparisons always pass, so expired or not-yet-active tokens are accepted. The verifier cache also derives infinite bounds, so entries created under this configuration can stay valid until eviction. Exploitation requires an application administrator or someone with an equivalent configuration path to set clockTolerance to Infinity, and the weaknesses are CWE-613 and CWE-682.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00341 27th percentileScored 2026-11-07
Fix Fixed fast-jwt (nearform): 6.3.0fast-jwt (npm): 6.3.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nearformfast-jwtbefore 6.3.06.3.0Patch availableCNA
—fast-jwt (npm)before 6.3.06.3.0Patch availableGHSA-687g-22h4-j4w4
  • fast-jwt Vendornearform Affected before 6.3.0 Fixed in 6.3.0 Patch available CNA
  • fast-jwt (npm) Vendor— Affected before 6.3.0 Fixed in 6.3.0 Patch available GHSA-687g-22h4-j4w4

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:nearform:fast-jwt:*:*:*:*:*:*:*:*——nearform
  • cpe:2.3:a:nearform:fast-jwt:*:*:*:*:*:*:*:* Versions — — ·nearform

Remediation

Upgrade fast-jwt to version 6.3.0, which fixes the issue. Affected versions are those before 6.3.0.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA fast-jwt (nearform) Fixed in 6.3.0
  • Fix · GHSA-687g-22h4-j4w4 fast-jwt (npm) Fixed in 6.3.0 Advisory →

Timeline

  1. 2026-10-09 Threatist record created from CVE-2026-107721
  2. 2026-10-09 Alias added: GHSA-687g-22h4-j4w4
  3. 2026-10-10 CISA SSVC decision points changed
  4. 2026-10-10 Priority changed: MEDIUM → LOW

References

Other 4

  • TI-2026-69702 Incomplete fix in fast-jwt enables RSA to HS256 algorithm confusion CVSS 3.1CRITICAL 9.8
  • TI-2026-27174 fast-jwt has an incomplete fix for CVE-2023-48223: JWT Algorithm Confusion via Whitespace-Prefixed RSA Public Key CVSS 3.1CRITICAL 9.1
  • TI-2025-37324 get-jwks poisoned JWKS cache allows post-fetch issuer validation bypass CVSS 3.0CRITICAL 9.4
  • TI-2026-27245 fast-jwt accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation) CVSS 3.1HIGH 7.5
  • TI-2026-69684 Claim validator bypass in fast-jwt when JWT payload is a JSON array CVSS 3.1HIGH 8.1
  • TI-2026-69695 fast-jwt accepts public JWK JSON as HMAC key, enabling token forgery CVSS 3.1HIGH 7.4
See all 15 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences