GHSA-hq85-5cpj-mr62 uv's bundled CA store trusts an emSign root whose intermediate CA keys are compromised
Attackers with compromised CA keys can perform man-in-the-middle attacks against uv's default TLS verification, requiring an upgrade to remove the untrusted root.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is GHSA-hq85-5cpj-mr62?
GHSA-hq85-5cpj-mr62 is a vulnerability in uv, published on 20 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by GHSA-hq85-5cpj-mr62?
3 open source packages ship an affected version, including uv.
| Package | Affected | Fixed in |
|---|---|---|
uv PyPI | All versions | 0.13.4 |
uv PyPI | All versions | 0.13.4 |
uv PyPI | All versions | 0.13.4 |
How do I fix GHSA-hq85-5cpj-mr62?
Upgrade uv to 0.13.4 or later.
Is GHSA-hq85-5cpj-mr62 being exploited?
There is no known exploitation of GHSA-hq85-5cpj-mr62 in the wild and no public exploit code.
Sources
Also known as PYSEC-2026-4321.