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.
- 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
- None listed
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
Which versions are affected by CVE-2025-4437?
3 open source packages ship an affected version, including github.com/cri-o/cri-o.
| Package | 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.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-4437 being exploited?
There is no known exploitation of CVE-2025-4437 in the wild and no public exploit code.
Sources
Also known as GHSA-8f93-j3fx-72f3, GO-2025-3897.