CVE-2026-13622

Description

A symlink following vulnerability was found in KubeVirt's virt-handler migration proxy. During live migration, virt-handler dials Unix sockets inside the target virt-launcher pod via /proc//root/ paths using net.Dial() without symlink protection. These socket paths reside in qemu-owned directories writable by the virt-launcher user. An attacker with namespace edit and pods/exec permissions can replace a migration proxy socket with a symlink to the host CRI-O socket. Because virt-handler runs as root in the host mount namespace, absolute symlink targets resolve against the host filesystem, and the bidirectional io.Copy proxy relays attacker-controlled bytes to the container runtime, enabling full node compromise.

Statement

Red Hat has rated this vulnerability as Important impact. The vulnerable code is in the virt-handler component, a privileged DaemonSet running as root in the host mount namespace on every compute node. Its migration proxy dials Unix sockets inside target virt-launcher pods via /proc//root/ using net.Dial(), which follows symbolic links. Because virt-handler operates in the host mount namespace, absolute symlink targets resolve against the host root filesystem, enabling container-to-host escape.

Exploitation requires an authenticated user with namespace-level edit permissions (kubevirt.io:edit) and pods/exec access — standard permissions for VM operators. The impact of successful exploitation is complete node compromise via CRI-O socket access, bypassing all Kubernetes admission controls.

Mitigation

Restrict pods/exec permissions in namespaces that run virtual machines. The pods/exec RBAC permission is required for the attack — removing it from VM operator roles prevents exploitation.

Additionally, enable Kubernetes audit logging and monitor for kubectl exec commands targeting virt-launcher pods, especially during live migration events.

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score8.8N/A8.8
Attack VectorLocalN/ALocal
Attack ComplexityLowN/ALow
Privileges RequiredLowN/ALow
User InteractionNoneN/ANone
ScopeChangedN/AChanged
ConfidentialityHighN/AHigh
Integrity ImpactHighN/AHigh
Availability ImpactHighN/AHigh

Vector

Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Understanding the Weakness (CWE)

Integrity,Confidentiality,Availability

Technical Impact: Execute Unauthorized Code or Commands

The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.

Integrity

Technical Impact: Modify Files or Directories

The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.

Confidentiality

Technical Impact: Read Files or Directories

The attacker may be able read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.

Availability

Technical Impact: DoS: Crash, Exit, or Restart

The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of protection mechanisms such as authentication, it has the potential to lock out product users.

Acknowledgements

This issue was discovered by Huzaifa Sidhpurwala (Red Hat).

Frequently Asked Questions

Want to get errata notifications? Sign up here.