CVE-2026-20613: Apple Container Path Traversal Flaw

CVE-2026-20613 Overview

CVE-2026-20613 is a Path Traversal vulnerability affecting Apple's Container and Containerization software packages for Swift. The ArchiveReader.extractContents() function used by cctl image load and container image load commands performs no pathname validation before extracting an archive member. This allows a maliciously crafted archive to extract files into arbitrary user-writable locations on the system using relative pathnames (e.g., ../../../).

Critical Impact

Attackers can craft malicious container images that, when loaded by users, extract files to arbitrary locations on the host system, potentially leading to code execution, configuration tampering, or credential theft.

Affected Products

• Apple Container (versions prior to 0.8.0)
• Apple Containerization (versions prior to 0.21.0)
• Swift-based container management implementations using the vulnerable ArchiveReader component

Discovery Timeline

• 2026-01-23 - CVE-2026-20613 published to NVD
• 2026-01-27 - Last updated in NVD database

Technical Details for CVE-2026-20613

Vulnerability Analysis

This vulnerability falls under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as Path Traversal or Directory Traversal. The flaw exists in the archive extraction logic where the ArchiveReader.extractContents() function fails to sanitize or validate file paths contained within archive members before writing them to disk.

When a user loads a container image using the cctl image load or container image load commands, the application processes the image archive and extracts its contents. Without proper path validation, an attacker can include archive entries with relative path components (such as ../) that escape the intended extraction directory.

The local attack vector requires user interaction—a victim must load the malicious archive—but requires no authentication or special privileges to exploit. Successful exploitation can result in high impact to confidentiality, integrity, and availability of the system.

Root Cause

The root cause is the absence of pathname sanitization in the ArchiveReader.extractContents() function. The function directly uses filenames from archive entries without checking for path traversal sequences or validating that the resolved destination path remains within the intended extraction directory. This is a classic "Zip Slip" style vulnerability applied to container image archives.

Attack Vector

An attacker would craft a malicious container image archive containing entries with path traversal sequences in their filenames. When an unsuspecting user loads this image using the vulnerable container tools, files are written outside the expected directory structure.

The vulnerability can be exploited to:

• Overwrite configuration files (e.g., shell profiles, cron jobs)
• Plant malicious executables in common binary paths
• Modify or replace scripts that may be executed by other processes
• Exfiltrate or corrupt existing user data

The attack scenario involves distributing the malicious container image through container registries, direct file sharing, or other software distribution channels where container images are exchanged.

Detection Methods for CVE-2026-20613

Indicators of Compromise

• Unexpected file modifications in user-writable directories outside container storage paths
• Files with timestamps corresponding to container image load operations appearing in unexpected locations
• Presence of files with names or content associated with known malicious container images
• Unusual archive extraction activity writing to paths containing ../ sequences

Detection Strategies

• Monitor file system events for writes outside expected container image storage directories during cctl image load or container image load operations
• Implement file integrity monitoring on critical user-writable locations such as shell profiles, cron directories, and local bin paths
• Audit container image load operations and correlate with file system changes across the system
• Scan incoming container images for archive entries containing path traversal patterns before loading

Monitoring Recommendations

• Enable detailed logging for container management tool operations including cctl and container commands
• Configure SentinelOne to monitor for suspicious file writes that correlate with container operations
• Implement alerts for modifications to sensitive user configuration files following container image loads
• Review container image sources and implement allowlisting for trusted image registries

How to Mitigate CVE-2026-20613

Immediate Actions Required

• Upgrade Apple Container to version 0.8.0 or later immediately
• Upgrade Apple Containerization to version 0.21.0 or later immediately
• Audit recently loaded container images and verify the integrity of user-writable directories
• Temporarily restrict the use of cctl image load and container image load commands until patching is complete

Patch Information

Apple has addressed this vulnerability in Container version 0.8.0 and Containerization version 0.21.0. The fix implements proper pathname validation to ensure extracted files cannot escape the intended extraction directory. Organizations should prioritize upgrading to these patched versions.

For detailed patch information, refer to the GitHub Security Advisory GHSA-cq3j-qj2h-6rv3.

Workarounds

• Avoid loading container images from untrusted or unverified sources until the patch is applied
• Implement additional file system restrictions using sandboxing or mandatory access controls to limit where container tools can write files
• Pre-scan container image archives for path traversal patterns using third-party archive inspection tools before loading
• Use read-only file system mounts for critical directories during container image operations where feasible

# Verify installed versions and upgrade
# Check current container version
cctl version

# Update to patched versions using Swift Package Manager
swift package update container
swift package update containerization

# Verify the upgrade was successful
cctl version