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TI-2026-38774 Aliases CVE-2026-53776

Perry < 0.5.1166 JWT Expiration Bypass via verify_decode

Priority MEDIUM 48CWE-613Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-613.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00357 29th percentileScored 2026-11-07
Fix Fixed perry (PerryTS): 0.5.1166

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
PerryTSperrybefore 0.5.11660.5.1166Patch availableCNA
  • perry VendorPerryTS Affected before 0.5.1166 Fixed in 0.5.1166 Patch available CNA

Remediation

  • Fix · CNA perry (PerryTS) Fixed in 0.5.1166

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-53776
  2. 2026-10-23 EPSS moved to the 50th–90th percentile
  3. 2026-10-25 EPSS moved to the below the 50th percentile

References

Advisory 1

Other 1

  • TI-2026-38775 Perry < 0.5.1159 Path Traversal via ArtifactReady WebSocket CVSS 4.0HIGH 8.6

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences