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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.

PUBLISHED Reserved 2026-01-16 | Published 2026-01-21 | Updated 2026-01-21 | Assigner redhat




LOW: 3.1CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

Problem types

Time-of-check Time-of-use (TOCTOU) Race Condition

Product status

Default status
affected

Default status
unaffected

Default status
unaffected

Default status
unaffected

Timeline

2026-01-16:Reported to Red Hat.
2026-01-21:Made public.

Credits

Red Hat would like to thank Mohamed Amine ait Ouchebou (mrecho) (Indiesecurity) for reporting this issue.

References

access.redhat.com/security/cve/CVE-2026-1035 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2430314 (RHBZ#2430314) issue-tracking

cve.org (CVE-2026-1035)

nvd.nist.gov (CVE-2026-1035)

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