CVE-2026-53476: Assisted Migration Agent Path Traversal

CVE-2026-53476 Overview

CVE-2026-53476 is a path traversal vulnerability in the assisted-migration-agent component of the KubeVirt migration toolkit. An unauthenticated attacker on the same local area network (LAN) can deliver a crafted gzipped tarball that bypasses path sanitization checks. The flaw allows arbitrary file writes outside the intended extraction directory, which can lead to unauthorized code execution on the appliance. The weakness is categorized under CWE-59: Improper Link Resolution Before File Access and affects systems where the agent processes attacker-controlled archives without authentication.

Critical Impact
Unauthenticated adjacent-network attackers can write arbitrary files and achieve code execution on affected appliances.

Affected Products

kubev2v/assisted-migration-agent (Red Hat migration toolkit component)
Appliances that deploy the assisted-migration-agent for VM migration workflows
Downstream Red Hat distributions integrating the vulnerable agent

Discovery Timeline

2026-06-10 - CVE-2026-53476 published to NVD
2026-06-10 - Last updated in NVD database

Technical Details for CVE-2026-53476

Vulnerability Analysis

The assisted-migration-agent accepts gzipped tarball archives as part of its migration workflow. The extraction routine fails to properly validate entry paths and symbolic links inside the archive. An attacker constructs a malicious tarball containing entries with relative path components such as ../ or symbolic links pointing outside the extraction root. When the agent processes the archive, files are written to arbitrary locations on the host filesystem.

Because the attack vector is adjacent network and requires no authentication or user interaction, any host capable of reaching the agent on the LAN can initiate the attack. The scope change in the impact metrics indicates the vulnerability allows the attacker to affect resources beyond the agent's own security boundary.

Root Cause

The root cause is improper link resolution and missing canonicalization of archive entry paths before file access [CWE-59]. The extraction code trusts the archive's internal path metadata rather than enforcing that resolved paths remain within the intended target directory. Symlink entries inside the tarball are followed during extraction, enabling redirection of file writes to attacker-chosen destinations.

Attack Vector

The attacker positions a host on the same LAN as the vulnerable agent. They construct a gzipped tarball containing path traversal sequences or malicious symlinks. The crafted archive is delivered to the agent through its normal ingestion interface. Upon extraction, the agent writes attacker-controlled content to sensitive system locations such as service unit files, cron directories, or SSH authorized key files. The next service activation or scheduled task triggers execution of the attacker's payload. Technical remediation details are available in the GitHub Pull Request #256 and the Red Hat CVE Advisory.

Detection Methods for CVE-2026-53476

Indicators of Compromise

Unexpected files created outside the agent's designated extraction directory, particularly in /etc/, /usr/local/bin/, /root/.ssh/, or systemd unit paths
Tarball uploads to the agent originating from unrecognized LAN hosts
Symbolic links inside processed archives that resolve outside the extraction root
New cron entries, systemd units, or shell initialization file modifications coinciding with migration agent activity

Detection Strategies

Audit filesystem changes on appliances running assisted-migration-agent and correlate writes against the agent's expected output paths
Inspect archives received by the agent for entries containing ../ sequences or symlinks pointing outside the archive root before extraction
Monitor process execution chains spawned by the agent user account for unexpected child processes or shell activity

Monitoring Recommendations

Enable verbose logging on the assisted-migration-agent and ship logs to a centralized SIEM for retention and correlation
Alert on network connections to the agent's listening port from hosts outside an approved migration source allowlist
Track integrity of critical system directories using file integrity monitoring (FIM) tooling on appliance hosts

How to Mitigate CVE-2026-53476

Immediate Actions Required

Apply the upstream fix from kubev2v/assisted-migration-agent PR #256 or update to a vendor-patched build
Restrict network access to the agent's listening interface using firewall rules or network segmentation so only authorized migration controllers can reach it
Audit appliances for indicators of prior exploitation, including unexpected files and unauthorized SSH keys

Patch Information

The upstream fix is tracked in kubev2v/assisted-migration-agent pull request #256. Red Hat tracks downstream remediation in Bugzilla #2487233 and the Red Hat CVE Advisory. Operators running affected appliances should consult vendor channels for the specific patched build applicable to their deployment.

Workarounds

Place the agent on an isolated management VLAN reachable only by trusted migration orchestration hosts
Disable or quarantine the assisted-migration-agent service until the patched version is deployed if migration workflows are not actively in use
Implement strict ACLs or mutual TLS at a reverse proxy in front of the agent to limit which clients can submit archives

bash

# Example: restrict agent access to a specific management subnet using iptables
iptables -A INPUT -p tcp --dport <agent-port> -s 10.20.30.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport <agent-port> -j DROP