CVE-2026-107723 fast-jwt - Authentication Bypass

fast-jwt < 6.3.0 contains a broken authentication caused by accepting JSON array payloads in JWTs without proper claim validation, letting attackers bypass expiry, issuer, audience, subject, revocation, and replay protections, exploit requires attacker to produce or influence a validly signed token.

CVSS base score 8.1 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.36% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Authentication Bypass
Impact
Broken Authentication
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Published
8 October 2026
Updated
15 October 2026
Weakness
CWE-1287

Vendor fix

Update to version 6.3.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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