# CVE-2026-79651: Keycloak-services: keycloak-services: unauthenticated dos via unbounded locale caching

> Unauthenticated attackers can crash the Keycloak server by exhausting memory through unbounded locale caching in theme endpoints.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Sep 2026
- **Updated:** 25 Sep 2026
- **Also known as:** GHSA-8qv5-pjhw-3gx4

## What is CVE-2026-79651?

CVE-2026-79651 is a high-severity denial of service vulnerability in Red Hat Single Sign-On 7, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in the theme localization endpoints of the keycloak-services component, which is the core service responsible for authentication flows and theme management in Keycloak. The issue occurs because the system accepts arbitrary locale tags from unauthenticated requests and stores them in a permanent in-memory cache without limits. An attacker can exploit this by sending a large number of unique locale tags, eventually causing the server to run out of memory and crash.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-79651?


## How do I fix CVE-2026-79651?

No fix has been published for CVE-2026-79651 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-79651 being exploited?

There is no known exploitation of CVE-2026-79651 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-79651 and fix it if it is affected.

What it is: CVE-2026-79651 is a high-severity denial of service vulnerability in Red Hat Single Sign-On 7, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-79651 in the wild and no public exploit code.

Affected product: Red Hat Single Sign-On 7. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-79651/ (Markdown: https://insights.sbomify.com/CVE-2026-79651/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-79651
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-79651
- OSV: https://osv.dev/vulnerability/CVE-2026-79651

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-79651/
Summaries are generated and may contain mistakes; the official description above is the record.