# CVE-2026-39934: Growth Experiments ReassignMenteesJob runs as an infinite loop

> An attacker can trigger an infinite loop in the ReassignMenteesJob via a race condition, causing denial of service in MediaWiki GrowthExperiments.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Apr 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-cgh3-rgf8-476j

## What is CVE-2026-39934?

CVE-2026-39934 is a medium-severity vulnerability in Mediawiki - GrowthExperiments Extension, published on 7 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Loop with unreachable exit condition ('infinite loop') vulnerability in The Wikimedia Foundation Mediawiki - GrowthExperiments Extension allows Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions. This issue was remediated only on the `master` branch.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2026-39934?


## How do I fix CVE-2026-39934?

No fix has been published for CVE-2026-39934 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-39934 being exploited?

There is no known exploitation of CVE-2026-39934 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-39934 and fix it if it is affected.

What it is: CVE-2026-39934 is a medium-severity vulnerability in Mediawiki - GrowthExperiments Extension, published on 7 Apr 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-2026-39934 in the wild and no public exploit code.

Affected product: Mediawiki - GrowthExperiments Extension. 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-2026-39934/ (Markdown: https://insights.sbomify.com/CVE-2026-39934/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-39934
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-39934
- OSV: https://osv.dev/vulnerability/CVE-2026-39934

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-39934/
Summaries are generated and may contain mistakes; the official description above is the record.