Cri-o: large /etc/passwd file may lead to denial of service

published 2025-08-20 14 mo ago modified 2026-09-26 44 d ago also GHSA-8f93-j3fx-72f3 , GO-2025-3897 , EUVD-2025-28020

cvss: 5.7; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 16%
public exploits: 0; none known

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.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-4437 updated 2026-09-01 cvss 5.7

cri-o: Large /etc/passwd file may lead to Denial of Service

Red Hat OpenShift Container Platform 4 cri-o, openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
affected: workaround, no fix available “As for now there's no available mitigation for this flaw.”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 14 mo ago (2025-08-20)

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.7	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
GitHub	3.1	5.7	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
go	github.com/cri-o/cri-o	<=1.33.3 all versions	no fix listed

Affected products

Red Hat Red Hat OpenShift Container Platform 4

Classification

Weakness

CWE-770 Allocation of Resources Without Limits or Throttling

References

access.redhat.com /security/cve/CVE-2025-4437
vdb-entry, web
bugzilla.redhat.com /show_bug.cgi?id=2375084
issue-tracking, web
nvd.nist.gov /vuln/detail/CVE-2025-4437
advisory
github.com /cri-o/cri-o
package
pkg.go.dev /vuln/GO-2025-3897
web
github.com /advisories/GHSA-8f93-j3fx-72f3
advisory

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary