CVE-2026-107720 fast-jwt - Authentication Bypass

fast-jwt < 6.3.1 contains an authentication bypass caused by accepting unsigned JWTs when key is empty or null and algorithms allowlist is non-empty, letting attackers bypass signature verification and submit arbitrary claims.

CVSS base score 7.4 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.26% 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:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Published
8 October 2026
Updated
15 October 2026
Weakness
CWE-20

Vendor fix

Update to version 6.3.1 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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