EUVD-2026-44661
GHSA-9gq4-2485-q63q
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attacker needs local low-privilege ability to set container env vars (AV:L/PR:L), no interaction, and injecting a privileged /etc/passwd entry yields full container compromise (C/I/A:H).
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
Lifecycle Timeline
3DescriptionCVE.org
A flaw was found in CRI-O. The fix for a previous vulnerability (CVE-2022-4318) was incorrect, allowing it to be bypassed. An attacker capable of setting environment variables on a container can inject a newline character into the HOME environment variable. This issue allows the addition of arbitrary lines into /etc/passwd by use of a specially crafted environment variable.
AnalysisAI
Privilege escalation in CRI-O (the OCI container runtime used by Red Hat OpenShift Container Platform 4 and many Kubernetes clusters) lets an attacker who can set container environment variables inject a newline into the HOME variable and append arbitrary lines to /etc/passwd, enabling creation of a rootful or otherwise privileged account inside the container. It is a bypass of the incomplete fix for CVE-2022-4318, whose HOME sanitization was insufficient. No public exploit identified at time of analysis and it is not listed in CISA KEV.
Technical ContextAI
CRI-O is the Kubernetes-native Container Runtime Interface implementation that OpenShift ships as its default runtime. During container setup, setupContainerUser in server/container_create.go derives user/home data from the HOME environment variable. Because the value was not validated for embedded newline characters, a crafted HOME (e.g. '/root:/sbin/nologin\ntest::0:0::/:/bin/bash') is interpreted as multiple lines when materialized into the container's /etc/passwd - a newline/CRLF-injection class flaw (NVD lists CWE as N/A). The upstream fix (cri-o/cri-o PR #6450, reinforced by #6524) rejects any HOME value containing a newline. The root cause is that the original CVE-2022-4318 remediation did not fully strip or reject newline sequences, leaving the sanitizer bypassable.
RemediationAI
Upstream fix available (PR/commit); released patched version not independently confirmed - apply the CRI-O update that includes cri-o/cri-o PR #6450 (https://github.com/cri-o/cri-o/pull/6450) and the follow-up PR #6524 (https://github.com/cri-o/cri-o/pull/6524), which reject any HOME environment value containing a newline. For OpenShift, install the errata/patched CRI-O RPM referenced in the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-15809 once published. Until patched, restrict who can set arbitrary environment variables on containers: enforce admission control (e.g. OPA/Gatekeeper or a Kubernetes admission webhook) to reject pod specs that set a HOME env var or that contain newline/control characters in env values, and tighten RBAC so untrusted users cannot create or mutate pods; the trade-off is that legitimate workloads relying on custom HOME values are blocked and admission policies add operational overhead.
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Same weakness CWE-116 – Improper Encoding or Escaping of Output
View allSame technique Authentication Bypass
View allVendor StatusVendor
SUSE
Severity: ImportantShare
External POC / Exploit Code
Leaving vuln.today