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Fencer Intel
critical —

GHSA-hq85-5cpj-mr62 json

uv's bundled CA store trusts an emSign root whose intermediate CA keys are compromised

published 23d ago modified 12d ago also PYSEC-2026-4321

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
—
no score, EPSS covers CVEs only
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi uv 0.13.4

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Affected packages

ecosystem package affected fixed in
pypi uv
<0.13.4
0.13.4

Classification

Weakness
  • CWE-295 Improper Certificate Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of astral-sh/uv published their own advisory on GitHub. Reviewed sources take precedence over it.