CVE-2026-6647

HIGH
MEDIUM Priority: 0.02 BB Relevance: 65/100
Published: 2026-10-28 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction Scope Change

CVSS Vector Breakdown

AV: Network
AC: Low
PR: Low
UI: None
S: Changed
C: Low
I: Low
A: Low

Description

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.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
WSO2 WSO2 Identity Server 7.2.0 < 7.2.0.21

Bug Bounty Relevance

65 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

7.4 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L

EPSS — Exploitation Probability

0.21%
Raw Score 0.002120
Percentile 11.5%
Date 2026-10-29

Intelligence Sources

mitre ref →
nvd ref →