Vulnerability record/PUBLISHED/Published Jun 16, 2026 15:18:53 UTC
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.
Base score9.3/ 10
SeverityCriticalCVSS 4.0
Exploitability / impact
CVSS metric breakdown
Base severityCritical
Attack vectorNetworkAV
Attack complexityLowAC
Attack requirementsNoneAT
Privileges requiredNonePR
User interactionNoneUI
Vulnerable system confidentialityHighVC
Vulnerable system integrityHighVI
Vulnerable system availabilityNoneVA
Subsequent system confidentialityNoneSC
Subsequent system integrityNoneSI
Subsequent system availabilityNoneSA
CVSS vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NCVSS communicates standardized severity and impact characteristics. It does not establish whether a system is exploitable in your specific environment.
Record context
CVE Numbering AuthorityVulnCheck
Last updatedNov 8, 2026 14:05:03 UTC
PublishedJun 16, 2026 15:18:53 UTC
ReservedJun 10, 2026 20:14:32 UTC
Credits
- Katriel Moses
- VulnCheck