CVE•Published 2026-04-06•Modified 2026-04-10•0 articles on news•5 live references•NVD data

CVE-2026-35042Nearform · Fast-jwt

Vulnerability data via NVD (ingested)

CVSS v3.1

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS percentile

—

Weaknesses (CWE)

CWE-345Insufficient Verification of Data Authenticity CWE-636Not Failing Securely ('Failing Open')

Description

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 fast-jwt does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC.

Timeline

Published 2026-04-06

Modified 2026-04-10

External references

NVD MITRE Exploit-DB Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common). Live host counts are a Premium feature.

Shodan · vuln tag

vuln:CVE-2026-35042

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Nearform Fast-jwt"

All exposed Nearform Fast-jwt instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Fast-jwt"

HTTP body or banner mentions "Fast-jwt" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-35042