What’s Vulnerable › Vulnerabilities

CVE-2026-53776: Perry < 0.5.1166 JWT Expiration Bypass via verify_decode

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-16 · updated 2026-10-25
• Weakness: CWE-613

Description

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.

Affected products

• PerryTS perry: before 0.5.1166 — fixed in 0.5.1166

How to fix

Upgrade to a fixed version: PerryTS perry 0.5.1166. Check the vendor advisory for mitigations.

References

• https://github.com/PerryTS/perry/releases/v0.5.1166
• https://github.com/PerryTS/perry/security/advisories/GHSA-5324-c68v-8w62
• https://www.vulncheck.com/advisories/perry-jwt-expiration-bypass-via-verify-decode

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