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Fencer Vulns
high 7.4

CVE-2026-6647 json

Incomplete OAuth Token Revocation via Case Mismatch in WSO2 Identity Server Allows Continued Access After Lifecycle Events

published 2026-10-28 11 d ago modified 2026-10-29 10 d ago also EUVD-2026-112401

cvss
7.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

In deployments of WSO2 Identity Server configured with a case-insensitive user store and a case-sensitive database for identity data, mismatches in username case handling can occur. This inconsistency results in OAuth token revocation operations failing to correctly identify usernames containing mixed-case characters during certain lifecycle events, preventing tokens from being invalidated.

A malicious actor can exploit this vulnerability by possessing a valid access or refresh token associated with a mixed-case username. In affected configurations, these tokens may not be revoked when expected. The actor can then leverage these unrevoked tokens, before their expiry, to continue performing actions that should have been restricted, effectively bypassing intended access controls.

Patch / fix

  • WSO2 WSO2 Identity Server 7.2.0.21
  • WSO2 WSO2 Carbon OAuth 7.0.385.17, 7.5.23

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
11 d ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L

Affected products

  • WSO2 WSO2 Identity Server
  • WSO2 WSO2 Carbon OAuth

Classification

Weakness
  • CWE-613 DEPRECATED: Insufficient Session Expiration

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.