CVE-2026-1035
Org.keycloak.protocol.oidc: keycloak refresh token reuse bypass via toctou race condition
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.
INFO
Published Date :
Jan. 21, 2026, 6:15 a.m.
Last Modified :
April 15, 2026, 12:35 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 3.1 | LOW | MITRE-CVE |
Solution
- Update Keycloak to the latest version.
- Ensure strict refresh token rotation is properly configured.
- Review and test token management logic.
Public PoC/Exploit Available at Github
CVE-2026-1035 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-1035.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-1035 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-1035
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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Shell
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-1035 vulnerability anywhere in the article.
-
The Cyber Express
New EU Vulnerability Platform GCVE Goes Live, Reducing Reliance on Global Systems
Europe’s long-running conversation about digital autonomy quietly crossed a milestone with the launch of a new public vulnerability platform. The EU Vulnerability Database, created under the GCVE init ... Read more
The following table lists the changes that have been made to the
CVE-2026-1035 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
Apr. 02, 2026
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2026:6477 Added Reference https://access.redhat.com/errata/RHSA-2026:6478 -
New CVE Received by [email protected]
Jan. 21, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N Added CWE CWE-367 Added Reference https://access.redhat.com/security/cve/CVE-2026-1035 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2430314