Vulnerability details
CVE-2026-53776
PerryTS perry
Perry < 0.5.1166 JWT Expiration Bypass via verify_decode
CVSS 4.0
9.3Critical
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.3Critical | 4.0 | CVEProject cvelistV5 (CNA) (VulnCheck) | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| 9.1Critical | 3.1 | CVEProject cvelistV5 (CNA) (VulnCheck) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| PerryTS | perry | v < 0.5.1166 | CVEProject cvelistV5 (CNA) |
References and advisories
3- https://github.com/PerryTS/perry/releases/v0.5.1166 release-notes
- https://github.com/PerryTS/perry/security/advisories/GHSA-5324-c68v-8w62 vendor-advisory
- https://www.vulncheck.com/advisories/perry-jwt-expiration-bypass-via-verify-decode third-party-advisory
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Details
- Published
- 2026-06-16
- Last updated
- 2026-11-08
- State
- Published
- Assigner (CNA)
- VulnCheck
Exploit prediction (EPSS)
0.35%
Probability of exploitation in 30 days
29.6%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-613Insufficient Session Expiration