# CVE-2026-1035: Org.keycloak.protocol.oidc: keycloak refresh token reuse bypass via toctou race condition

> Attackers can bypass refresh token rotation via a race condition, issuing multiple access tokens from a single refresh token in Keycloak.

- **Severity:** Low 3.1 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Jan 2026
- **Updated:** 2 Apr 2026
- **Also known as:** GHSA-m2w5-7xhv-w6fh, MINI-9mhq-rqp9-8prm, UBUNTU-CVE-2026-1035

## What is CVE-2026-1035?

CVE-2026-1035 is a low-severity vulnerability in Red Hat JBoss Enterprise Application Platform 8, published on 21 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-1035?

2 open source packages ship an affected version, including org.keycloak:keycloak-services.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.keycloak:keycloak-services` | Maven | All versions to 26.2.5 | None |
| `org.keycloak:keycloak-services` | Maven | All versions to 26.2.5 | None |

## How do I fix CVE-2026-1035?

Apply the vendor's patch.

## Is CVE-2026-1035 being exploited?

There is no known exploitation of CVE-2026-1035 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-1035 and fix it if it is affected.

What it is: CVE-2026-1035 is a low-severity vulnerability in Red Hat JBoss Enterprise Application Platform 8, published on 21 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-1035 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.keycloak:keycloak-services (Maven): affected all versions up to 26.2.5; no fix listed
- org.keycloak:keycloak-services (Maven): affected all versions up to 26.2.5; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-1035/ (Markdown: https://insights.sbomify.com/CVE-2026-1035/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-1035
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-1035
- OSV: https://osv.dev/vulnerability/CVE-2026-1035

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-1035/
Summaries are generated and may contain mistakes; the official description above is the record.