CVE-2026-35041

What it is

fast-jwt provides fast JSON Web Token (JWT) implementation. From 5.0.0 to 6.2.0, a denial-of-service condition exists in fast-jwt when the allowedAud verification option is configured using a regular expression. Because the aud claim is attacker-controlled and the library evaluates it against the supplied RegExp, a crafted JWT can trigger catastrophic backtracking in the JavaScript regex engine, resulting in significant CPU consumption during verification. This vulnerability is fixed in 6.2.1.

At a glance

Exploitability

Can be exploited over the network with an admin-level account, but needs a user to act. High risk of service disruption.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-04-09 16:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 22:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 4.2 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-04-09 16:16 UTC

Last modified

2026-10-26 22:10 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-1333

Record status

Analyzed

Affected

• Nearform fast-jwt < 6.2.1

Attack profile CVSS 3.1 · 4.2

Attack vector

Network

Complexity

High

Privileges needed

High

User interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-35041.md and follow it. Check whether this project is affected by CVE-2026-35041. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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