Compromise of PyTorch Lightning PyPi Package Versions

# Security Advisory: Compromise of PyTorch Lightning PyPI Package Versions **Published:** 2026-04-30 **Last Updated:** 2026-05-12 **Github Advisory:** [CVE-2026-44484](https://github.com/advisories/GHSA-w37p-236h-pfx3) We have identified a security incident affecting certain versions of one of our PyPI packages. ## What happened We have determined that one or more released versions of this package have been compromised and include malicious code. Our current investigation indicates that the affected versions have introduced functionality consistent with a credential harvesting mechanism. We are still actively analysing the scope and behaviour of the code. At this stage, the root cause of the compromise is still under investigation. ## What versions are affected We are currently working to confirm the exact set of impacted versions. We have determined the following versions as affected and ask that you delete them from your systems: - `2.6.2` - `2.6.3` We will update this advisory if the versions impacted by this vulnerability change. ## What you should do immediately If you have installed or are running any potentially affected versions: - Assume the environment may be compromised - Immediately rotate all credentials and secrets that may have been exposed, including: - API keys - Access tokens - SSH keys - Service account credentials - Rebuild affected systems from a known clean state - Pin PyTorch Lightning to version `2.6.1` - Review logs for any suspicious or unauthorised activity ## Actions we have taken - Quarantined malicious versions from PyPI - Recommend using version `2.6.1`: https://github.com/Lightning-AI/pytorch-lightning/releases/tag/2.6.1 - Revoked and rotated all internal credentials associated with our release process - Initiated a full investigation into the compromise ## Ongoing investigation We are actively working to: - Identify the exact mechanism of compromise - Confirm the full set of affected versions - Determine the behaviour and impact of the malicious code - Assess any downstream impact to users We will provide updates as soon as more information becomes available. ## Commitment to transparency We take the security of our users and the integrity of our software supply chain extremely seriously. We will continue to share timely and accurate updates as our investigation progresses. ## Contact If you have questions or believe you may be impacted, please contact us at: **security@lightning.ai**

CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity from

GitHub (reviewed advisory)

Weakness

CWE-506

Also known as

CVE-2026-44484, PYSEC-2026-3973, PYSEC-2026-508

• github.com/Lightning-AI/pytorch-lightning/security/advisories/GHSA-w37p-236h-pfx3
• nvd.nist.gov/vuln/detail/CVE-2026-44484
• github.com/Lightning-AI/pytorch-lightning