CVE-2026-46383: CVE-2026-46383: Arbitrary File Overwrite via Path Traversal (TarSlip) in Microsoft APM

#security #cve #cybersecurity

CVE-2026-46383: Arbitrary File Overwrite via Path Traversal (TarSlip) in Microsoft APM

Vulnerability ID: CVE-2026-46383
CVSS Score: 5.5
Published: 2026-05-15

A path traversal vulnerability exists in the legacy-bundle probing logic of Microsoft APM, an open-source dependency manager for AI agents. On Windows systems using Python versions prior to 3.12, this allows local attackers to overwrite arbitrary files via a crafted tarball.

TL;DR

Microsoft APM < 0.13.0 on Windows is vulnerable to an arbitrary file overwrite during archive extraction. Exploitation requires user interaction to install a crafted tarball.

⚠️ Exploit Status: POC

Technical Details

CVE ID: CVE-2026-46383
CWE ID: CWE-22
CVSS Score: 5.5
Attack Vector: Local (User Interaction Required)
Impact: High Integrity (Arbitrary File Overwrite)
Exploit Status: Proof of Concept
CISA KEV: Not Listed

Affected Systems

Microsoft APM on Windows environments using Python < 3.12
microsoft/apm: < 0.13.0 (Fixed in: 0.13.0)

Code Analysis

Commit: 77d1dda

Fix path traversal in legacy-bundle probe extraction

Mitigation Strategies

Upgrade the software dependency
Upgrade the Python runtime environment
Implement strict source validation for installed bundles
Enforce least privilege execution

Remediation Steps:

Identify all deployments of microsoft/apm currently in use.
Update the package to version 0.13.0 using the appropriate package manager.
Ensure the host system is running Python 3.12 or later to benefit from native extraction filters.
Audit the filesystem for unexpectedly modified files if untrusted bundles were installed prior to patching.