# CVE-2021-43979: Race condition in n/a

> Attackers can bypass access control policies in OPA Gatekeeper due to a race condition during data replication, allowing unauthorized actions.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Nov 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-v8hv-78vf-x9fr

## What is CVE-2021-43979?

CVE-2021-43979 is a medium-severity vulnerability in n/a, published on 17 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Styra Open Policy Agent (OPA) Gatekeeper through 3.7.0 mishandles concurrency, sometimes resulting in incorrect access control. The data replication mechanism allows policies to access the Kubernetes cluster state. During data replication, OPA/Gatekeeper does not wait for the replication to finish before processing a request, which might cause inconsistencies between the replicated resources in OPA/Gatekeeper and the resources actually present in the cluster. Inconsistency can later be reflected in a policy bypass. NOTE: the vendor disagrees that this is a vulnerability, because Kubernetes states are only eventually consistent

Weakness: CWE-670 (Always-Incorrect Control Flow Implementation)

## Which versions are affected by CVE-2021-43979?

It affects 1 product.


Products: Openpolicyagent Gatekeeper.

## How do I fix CVE-2021-43979?

No fix has been published for CVE-2021-43979 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-43979 being exploited?

There is no known exploitation of CVE-2021-43979 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-43979 and fix it if it is affected.

What it is: CVE-2021-43979 is a medium-severity vulnerability in n/a, published on 17 Nov 2021. 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-2021-43979 in the wild and no public exploit code.

Affected product: n/a. 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-2021-43979/ (Markdown: https://insights.sbomify.com/CVE-2021-43979/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-43979
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-43979
- OSV: https://osv.dev/vulnerability/CVE-2021-43979

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-43979/
Summaries are generated and may contain mistakes; the official description above is the record.