---
id: "CVE-2025-71437"
kind: "vulnerability"
aliases: ["CVE-2025-71437"]
title: "uv: malicious sdist writes files outside install directory via symlinks"
severity: "high"
cvss: 8.7
epss: 0.00285
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ci", "developer-machines", "package", "python", "uv"]
not_affected_if: ["no-sdist-installs", "uv-0.8.22-or-later"]
published_at: "2026-10-21T01:17:19+00:00"
first_seen_at: "2026-10-23T21:57:27+00:00"
updated_at: "2026-10-24T13:15:55+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-71437", "first_seen_at": "2026-10-23T21:57:27+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2025-71437", "first_seen_at": "2026-10-24T13:15:55+00:00"}]
---

# uv: malicious sdist writes files outside install directory via symlinks

Astral uv before 0.8.22 extracts source distribution tar files without blocking crafted symlink chains, so a malicious sdist can redirect writes outside the extraction prefix. An attacker who publishes a bad package gets arbitrary file writes on the machine of anyone who installs it.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

Run uv --version and check whether the version is below 0.8.22.

## Fix

Upgrade uv to 0.8.22 or later.

## Timeline

- 2026-10-23T21:57:27+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2025-71437
- 2026-10-24T13:15:55+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2025-71437

## From the sources

Astral uv before 0.8.22 contains a path traversal vulnerability in source distribution (sdist) tar extraction that allows a specially crafted sequence of symlinks to redirect file writes outside the intended extraction prefix. Attackers can publish a malicious sdist that, when installed by a victim, writes arbitrary files to filesystem locations outside the installation prefix.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_