CVE-2026-53776
Published: 16 June 2026
Summary
CVE-2026-53776 is a critical-severity Insufficient Session Expiration (CWE-613) vulnerability. Its CVSS base score is 9.3 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Web Session Cookie (T1550.004); ranked at the 27.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-37126
Vulnerability details
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
JWT expiration bypass directly enables indefinite use of valid bearer tokens (T1550.004) and continued authenticated access via existing accounts (T1078).
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Locks the device (typically after inactivity) until re-authentication, addressing insufficient session expiration by preventing indefinite access.
Automatically terminating sessions after a defined period directly enforces session expiration, preventing indefinite session lifetimes that attackers can exploit.
Re-authentication after inactivity or time-based triggers prevents indefinite use of potentially hijacked or stale sessions.
Terminating sessions and network connections upon completion prevents insufficient session expiration.
Directly enforces termination of network sessions after inactivity or end-of-session, preventing indefinite session lifetime.
Consistent clocks across systems allow session expiration and timeout enforcement to function as intended in distributed environments.
When the non-persistent artifact is a session or connection, mandatory termination implements the missing expiration that CWE-613 describes.
Timed refresh of session-related information or on-demand generation plus deletion implements proper session expiration.