Vulnerability · Published Jun 12, 2026 · Assigned by apache
CVE-2026-50631Apache CXF: OAuth2: TOCTOU Race Condition in Refresh Token Processing
High 7.4
In plain English
A high-severity security flaw in Apache CXF from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
A race condition in AbstractOAuthDataProvider allows concurrent requests using the same Refresh Token to bypass single-use semantics and generate multiple valid Access Tokens, when 'recycleRefreshTokens' is set to false. A leaked refresh token can be replayed concurrently by multiple attackers or threads. Users are recommended to upgrade to versions 4.2.2 or 4.1.7 or 3.6.12, which fixes this issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Maven | org.apache.cxf:cxf-rt-rs-security-oauth2 | 4.2.2 | GHSA-83r6-96m8-r52p |
| Maven | org.apache.cxf:cxf-rt-rs-security-oauth2 | 4.1.7 | GHSA-83r6-96m8-r52p |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache CXF | 4.2.0 – before 4.2.24.0.0 – before 4.1.70 – before 3.6.12 |
Weakness: CWE-367 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N