Org.keycloak.protocol.oidc: keycloak refresh token reuse bypass via toctou race condition
Summary
| CVE | CVE-2026-1035 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-01-21 06:15:46 UTC |
| Updated | 2026-04-02 14:16:25 UTC |
| Description | A flaw was found in the Keycloak server during refresh token processing, specifically in the TokenManager class responsible for enforcing refresh token reuse policies. When strict refresh token rotation is enabled, the validation and update of refresh token usage are not performed atomically. This allows concurrent refresh requests to bypass single-use enforcement and issue multiple access tokens from the same refresh token. As a result, Keycloak’s refresh token rotation hardening can be undermined. |
Risk And Classification
Primary CVSS: v3.1 3.1 LOW from [email protected]
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
EPSS: 0.000110000 probability, percentile 0.012280000 (date 2026-04-07)
Problem Types: CWE-367 | CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 3.1 | LOW | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | CNA | CVSS | 3.1 | LOW | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4-14 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4.11-1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4-14 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4.11 | Not specified | Not specified |
| CNA | Red Hat | Red Hat JBoss Enterprise Application Platform 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | Not specified | Not specified |
| CNA | Red Hat | Red Hat Single Sign-On 7 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/errata/RHSA-2026:6478 | [email protected] | access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-1035 | [email protected] | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/errata/RHSA-2026:6477 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Mohamed Amine ait Ouchebou (mrecho) (Indiesecurity) for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-01-16T06:45:27.223Z | Reported to Red Hat. |
| CNA | 2026-01-21T00:00:00.000Z | Made public. |
Workarounds
CNA: To mitigate this issue, configure the `refreshTokenMaxReuse` policy in Keycloak to a value greater than zero. This prevents the race condition by allowing a limited number of reuses for refresh tokens, thereby maintaining the integrity of the Refresh Token Rotation hardening measure. Consult Keycloak documentation for specific configuration instructions. Changes to Keycloak configuration typically require a service restart or redeployment to take effect.