# CVE-2025-4437: Cri-o: large /etc/passwd file may lead to denial of service

> Attackers can cause denial of service by launching containers with non-existent users and large /etc/passwd files, exhausting host memory.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 20 Aug 2025
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-8f93-j3fx-72f3, GO-2025-3897

## What is CVE-2025-4437?

CVE-2025-4437 is a medium-severity denial of service vulnerability in Red Hat OpenShift Container Platform 4, published on 20 Aug 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

There's a vulnerability in the CRI-O application where when container is launched with securityContext.runAsUser specifying a non-existent user, CRI-O attempts to create the user, reading the container's entire /etc/passwd file into memory. If this file is excessively large, it can cause the a high memory consumption leading applications to be killed due to out-of-memory. As a result a denial-of-service can be achieved, possibly disrupting other pods and services running in the same host.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2025-4437?

3 open source packages ship an affected version, including github.com/cri-o/cri-o.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/cri-o/cri-o` | Go | All versions | None |
| `github.com/cri-o/cri-o` | Go | All versions to 1.33.3 | None |
| `github.com/cri-o/cri-o` | Go | All versions to 1.33.3 | None |

## How do I fix CVE-2025-4437?

No fix has been published for CVE-2025-4437 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-4437 being exploited?

There is no known exploitation of CVE-2025-4437 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-4437 and fix it if it is affected.

What it is: CVE-2025-4437 is a medium-severity denial of service vulnerability in Red Hat OpenShift Container Platform 4, published on 20 Aug 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-4437 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/cri-o/cri-o (Go): affected all versions; no fix listed
- github.com/cri-o/cri-o (Go): affected all versions up to 1.33.3; no fix listed
- github.com/cri-o/cri-o (Go): affected all versions up to 1.33.3; 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-2025-4437/ (Markdown: https://insights.sbomify.com/CVE-2025-4437/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-4437
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-4437
- OSV: https://osv.dev/vulnerability/CVE-2025-4437

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-4437/
Summaries are generated and may contain mistakes; the official description above is the record.