What is CVE-2026-35042?

CVE-2026-35042 is a high-severity vulnerability in Nearform Fast-jwt, classified under Insufficient Verification of Data Authenticity. CVSS score: 7.5/10. Published 2026-04-06.

How severe is CVE-2026-35042?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Nearform Fast-jwt

CVE-2026-35042

fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, fast-jwt does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that f…

EPSS: 0.000 (8.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Nearform Fast-jwt — versions <= 6.1.0

Weakness classification (CWE)

References

https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6 (x_refsource_CONFIRM)
https://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-35042?: CVE-2026-35042 is a high-severity vulnerability in Nearform Fast-jwt, classified under Insufficient Verification of Data Authenticity. CVSS score: 7.5/10. Published 2026-04-06.
How severe is CVE-2026-35042?: High severity. CVSS v3 base score is 7.5 out of 10.