CVE-2026-35041: nearform fast-jwt · ReDoS
Affects nearform fast-jwtSource CVE Database V5
Not known to be exploited · CVSS 4.2 Medium : upgrade to 6.2.1 when convenient.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.2.1
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 9 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade nearform fast-jwt to 6.2.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| nearformfast-jwt | Affected
| Fixed in
|
npmfast-jwtpkg:npm/fast-jwtOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade fast-jwt to version 6.2.1 or later where this vulnerability is fixed. Since the vendor advisory indicates the issue is resolved in 6.2.1, applying this official fix is the recommended remediation. No alternative mitigations or workarounds are provided.
Description
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.
References
- github.com/nearform/fast-jwt/security/advisories/GHSA-cjw9-ghj4-fwxf (opens in a new tab)
- github.com/nearform/fast-jwt/pull/595 (opens in a new tab)
- github.com/nearform/fast-jwt/commit/b0be0ca161593836a153d5180ca5358ad9b5de94 (opens in a new tab)
- github.com/nearform/fast-jwt/releases/tag/v6.2.1 (opens in a new tab)