Time-of-check Time-of-use (TOCTOU) Race Condition in Apache CXF - CVE-2026-50631
Published: August 25, 2026
Vulnerability identifier: #VU145228
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-50631
CWE-ID: CWE-367
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to generate multiple valid access tokens from a single refresh token.
The vulnerability exists due to a race condition in AbstractOAuthDataProvider when processing concurrent refresh token requests. A remote user can replay a leaked refresh token concurrently to generate multiple valid access tokens from a single refresh token.
The issue occurs only when 'recycleRefreshTokens' is set to false.
Affected software
Apache CXF
How to mitigate CVE-2026-50631
Install security update from vendor's website.
Apache CXF - addressed in versions 4.1.7, 4.2.2