Vulnerability in Perryts Perry
CVE-2026-53776
Perry before 0.5.1166 contains a JWT validation vulnerability that allows remote attackers to bypass token expiration by exploiting the unconditional setting of validate_exp = false in the verify_decode helper within the stdlib JWT verification path. Attackers in possession of a previously issued bearer token can present expired tokens to any jwt.verify() call and retain authenticated access indefinitely, bypassing force-expired sessions such as user logout or administrative revocation.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.006 (48.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.003
Affected products
- Perryts Perry — versions 0
Weakness classification (CWE)
References
- github.com/PerryTS/perry/releases/v0.5.1166 (release-notes)
- github.com/PerryTS/perry/security/advisories/GHSA-5324-c68v-8w62 (vendor-advisory)
- www.vulncheck.com/advisories/perry-jwt-expiration-bypass-via-verify-decode (third-party-advisory)
Frequently asked questions
- What is CVE-2026-53776?
- CVE-2026-53776 is a critical-severity vulnerability in Perryts Perry, classified under Insufficient Session Expiration. CVSS score: 9.1/10. Published 2026-06-16.
- How severe is CVE-2026-53776?
- Critical severity. CVSS v3 base score is 9.1 out of 10.