EUVD-2026-44661
GHSA-9gq4-2485-q63q
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain rights to set container env vars
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DeliveryCraft HOME with embedded newline
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ExploitCRI-O writes injected /etc/passwd line
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ExecutionPrivileged account created in container
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ImpactEscalate privileges inside container
Vulnerability Assessment
| Weakness |
CWE
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| Exploitation Conditions | The attacker must be able to set environment variables on a container that CRI-O creates - specifically the HOME variable - and inject a newline (\n) into its value so that /etc/passwd gains attacker-controlled lines. This requires a foothold that lets them influence the container/pod specification (e.g. Kubernetes API access to create or modify pods, a malicious image build, or a compromised orchestration path), and the target CRI-O must predate the PR #6450/#6524 newline-rejection fix. Limiting factors: it is a local vector (AV:L) requiring existing low privileges (PR:L) to control env vars, there is no remote unauthenticated path, and clusters that restrict env-var setting via admission control or RBAC block ordinary untrusted users. |
| Impact | The CVSS 3.1 vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (7.8, High) describes a local, low-privilege, no-interaction attack with high confidentiality, integrity and availability impact - consistent with the description: the attacker must already be able to influence a container's environment variables (PR:L) and operates locally (AV:L), but can then plant a privileged /etc/passwd entry. No EPSS score, no KEV listing, and no public POC are present in the provided data, so real-world exploitation appears targeted/low-frequency rather than mass-exploited; the primary risk is post-compromise or malicious-tenant privilege escalation in multi-tenant clusters. Note a data conflict: the intelligence tags include 'Authentication Bypass' and 'Confidential Compute Attestation,' which do not match the /etc/passwd-injection mechanism described - these tags are likely artifacts of Red Hat's affected-product mapping and should not be read as an independent auth-bypass primitive; verify with the Red Hat advisory. SSVC-style read: exploitation is not automatable at scale (requires the ability to set env vars on a target container), technical impact is total for the container, so prioritize where untrusted workloads or users can shape pod/container specs. |
| Exploit ScenarioDerived | A malicious tenant or a compromised CI pipeline with permission to define a pod's environment variables sets HOME to a value containing an embedded newline that crafts a second /etc/passwd entry (e.g. a UID 0 account with a login shell). When CRI-O provisions the container, the injected line is written to /etc/passwd, giving the attacker a privileged account inside the container for escalation. No public POC is identified, but the attack needs only local low-privilege ability to shape container env vars (AV:L/AC:L/PR:L). |
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Alert meAnalysisAIv1 – Jul 15, 2026
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.
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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Technical ContextAI · show details
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.
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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
DescriptionCVE.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.
Executive ViewAI
CRI-O container runtime vulnerability in Red Hat OpenShift and Kubernetes environments allows privilege escalation when attacker-controlled environment variables bypass HOME sanitization, enabling creation of unauthorized privileged accounts within containers. Organizations deploying containerized workloads face compromise of application isolation and potential lateral movement into privileged container contexts.
Restrict environment variable injection via Kubernetes admission webhooks and RBAC policies; implement runtime security monitoring to alert on unauthorized /etc/passwd modifications; enforce Pod Security Standards to disable privileged mode; segment container workloads with network policies; require image scanning and signed container manifests to prevent malicious environment variables at deployment time.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Affected Products (CPE)CVE.org
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