Is This vulnerability exploited in the wild?

No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

How severe is This vulnerability?

Critical severity, published 30 October 2026.

Which products and versions are affected?

pypa/gh-action-pypi-publish (GitHub Actions) <= 1.14.2; Pypa Gh-Action-Pypi-Publish 1.14.2 and earlier.

Is there a fix for This vulnerability?

Yes: fixed in 1.14.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is This vulnerability attacked?

It is attacked over the network.

Check whether you run pypa/gh-action-pypi-publish (GitHub Actions) or Pypa Gh-Action-Pypi-Publish at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

pypi-publish action improper certificate validation in Sigstore integration

Q: Is there a fix for This vulnerability?

Yes: fixed in 1.14.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is This vulnerability attacked?

It is attacked over the network.

Q: Am I affected?

Check whether you run pypa/gh-action-pypi-publish (GitHub Actions) or Pypa Gh-Action-Pypi-Publish at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Severity: critical · Published 2026-10-30

The pypi-publish GitHub Action, which automates publishing Python packages to PyPI with cryptographic signing via Sigstore, bundled a revoked Certificate Authority (emSign) in its trust store. This revocation was not reflected in the action's bundled certificates, creating a window where an attacker holding a compromised private key for that CA could forge valid-looking signatures and inject malicious code into PyPI packages during the trusted publishing workflow.

Vendors: GitHub Actions, Pypa.

Quick answers

Is This vulnerability exploited in the wild?: No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?: Critical severity, published 30 October 2026.
Which products and versions are affected?: pypa/gh-action-pypi-publish (GitHub Actions) <= 1.14.2; Pypa Gh-Action-Pypi-Publish 1.14.2 and earlier.
Is there a fix for This vulnerability?: Yes: fixed in 1.14.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?: It is attacked over the network.
Am I affected?: Check whether you run pypa/gh-action-pypi-publish (GitHub Actions) or Pypa Gh-Action-Pypi-Publish at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: 1.14.3

Technical details

The vulnerability is an improper certificate validation issue (CWE-295) where versions ≤1.14.2 bundled an outdated emSign root CA certificate through the certifi library, despite that CA being revoked by its issuer. Sigstore, which pypi-publish depends on for Trusted Publishing and Digital Attestations, relies on this TLS trust store for certificate chain validation. An attacker with the compromised CA private key could conduct a MITM attack or forge certificates to intercept or manipulate package publishing workflows, affecting confidentiality and integrity of published packages. The fix is available in version 1.14.3 and later.

Affected products

PyPA gh-action-pypi-publish 1.14.2 and earlier

Timeline

2026-10-21: disclosed
2026-10-30: advisory

References

https://github.com/pypa/gh-action-pypi-publish/security/advisories/GHSA-5xjx-3w67-w9x9

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