---
id: PYSEC-2026-4321
aliases:
  - GHSA-hq85-5cpj-mr62
title: >-
  uv's bundled CA store trusts an emSign root whose intermediate CA keys are
  compromised
summary: >-
  uv's bundled CA store trusts an emSign root whose intermediate CA keys are
  compromised
severity: none
vendor: uv
product: uv
ecosystem: pip
affected:
  - uv < 0.13.4
patched:
  - uv 0.13.4
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T22:00:02.616367477Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/PYSEC-2026-4321'
references:
  - url: 'https://github.com/astral-sh/uv/security/advisories/GHSA-hq85-5cpj-mr62'
  - url: >-
      https://github.com/certifi/python-certifi/security/advisories/GHSA-6q48-6c7w-9gw2
  - url: 'https://emudhra.we-have-a-problem.com'
  - url: 'https://github.com/astral-sh/uv'
  - url: >-
      https://groups.google.com/a/mozilla.org/g/dev-security-policy/c/0R3XLJL6FuE/m/0XofdebrAAAJ
  - url: 'https://pypi.org/project/uv'
  - url: 'https://github.com/advisories/GHSA-hq85-5cpj-mr62'
tags:
  - osv
  - pip
ingestedAt: '2026-10-21T11:54:42.747Z'
---

## Overview

By default, uv verifies TLS connections against a vendored copy of the `webpki-root-certs` bundle. Versions before 0.13.4 include the `emSign ECC Root CA - G3` root. Eight eMudhra intermediate CA certificates that chain to that root have compromised private keys, and the CA has revoked them.

An attacker with one of the compromised keys can issue certificates that uv accepts for any hostname, and can be used to issue certificates to enable MITM attacks.

uv 0.13.4 removes the root from its vendored bundle, following `webpki-root-certs` 1.0.10. Upgrade to 0.13.4 or later.

## Affected packages

- `uv < 0.13.4`

## Remediation

Upgrade to a patched release:

- `uv 0.13.4`