Paper/Archive/CVE-2026-35039

CVE-2026-35039

nearform fast-jwt — fast-jwt Affected by Cache Confusion via cacheKeyBuilder Collisions Can Return Claims From a Different Token (Identity/Authorization Mixup)

EPSS 0.2%CVSS 9.1

critical.is priorityof 100

CVSS 9.1 (CNA)9.1 / 10 × 3027.3 Not in CISA KEV+300.0 EPSS percentile 11.5.115 × 202.3 No public exploit+100.0 SSVC exploitation: none+100.0

Description · from the CVE record

fast-jwt provides fast JSON Web Token (JWT) implementation. From 0.0.1 to before 6.2.0, setting up a custom cacheKeyBuilder method which does not properly create unique keys for different tokens can lead to cache collisions. This could cause tokens to be mis-identified during the verification process leading to valid tokens returning claims from different valid tokens and users being mis-identified as other users based on the wrong token. Version 6.2.0 contains a patch.

Affected

ProductAffectedFixed inSource

fast-jwt>= 0.0.1, < 6.2.0–CNA

Scores by source

GitHub_M (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgithub.com/nearform/fast-jwt/security/advisories/GHSA-rp9m-7r4c-75qg refgithub.com/nearform/fast-jwt/commit/de121056c6415b58770c60640881eaec67ac4ceb