GitHub is rotating its GHES signing key following a cyber-attack to ensure the integrity of future updates. Engineers managing GHES instances must rotate GPG keys immediately to avoid update failures and maintain a secure, verified supply chain for their enterprise infrastructure.
May 26, 2026: GitHub recently detected a cyber-attack and immediately activated our response process to investigate, disrupt malicious activity, mitigate the attack, and deny the threat actor further access. It’s important to note that this investigation is still ongoing, and we will continue to provide details as appropriate.
Given the reality of threat actors and the advent of AI technologies, we need to do all we can to protect our customers. Considering the repositories that have been attacked and an abundance of caution, we are rotating keys, including the GitHub Enterprise Server signing key. This key is used to sign binaries for GitHub Enterprise Server to validate GitHub as the source during a manually initiated update process. All binaries hosted by GitHub are valid.
GitHub Enterprise Server customers need to take immediate action as described below. No action is required for GitHub Enterprise Cloud.
GitHub Enterprise Server administrators will need to rotate the GPG public keys in their instance. Admins can follow these instructions to do so using a GitHub developed script to streamline the process. If you’d like to independently verify the integrity of the script, its SHA256 digest is:
3009bf5cdef034e153008cc375a05ac0bdbb1a2a325b22adb300c028e3766b43For single node topology, run these commands:
$ curl -fsSL https://enterprise.github.com/security/2026-05-24/rotate-gpg.sh -o rotate-gpg.sh
$ chmod ug+x ./rotate-gpg.sh
$ ./rotate-gpg.sh
$ sudo ./rotate-gpg.sh For HA or cluster topology:
$ ghe-cluster-each -- curl -fsSL https://enterprise.github.com/security/2026-05-24/rotate-gpg.sh -o rotate-gpg.sh
$ ghe-cluster-each -- chmod ug+x ./rotate-gpg.sh
$ ghe-cluster-each -- ./rotate-gpg.sh
$ ghe-cluster-each -- sudo ./rotate-gpg.sh If the signing key is not rotated, future GitHub Enterprise Server version upgrades will fail verification with the following error message:
Error: The file provided is not a valid GitHub Enterprise Server package.Future patches and releases will be signed with the new key, and customers will need to rotate to the new public key before those patches and releases can be installed. Customers should ensure they only download GHES updates from the official GitHub.com source URL. GitHub recommends that customers prepare to take GHES security updates at an increased rate over the coming months.
As the information security landscape continues to evolve, we are prioritizing hardening our systems as new threats emerge. We’ll continue to update our community on noteworthy developments. We remain committed not only to keeping GitHub secure but also to helping secure the broader open source ecosystem.
Original blog post, published May 20, 2026: On Monday May 18, we detected and contained a compromise of an employee device involving a poisoned VS Code extension published by a third party. We removed the malicious extension version, isolated the endpoint, and began incident response immediately.
Our current assessment is that the activity involved exfiltration of GitHub-internal repositories only. The attacker’s current claims of ~3,800 repositories are directionally consistent with our investigation so far.
We have no evidence of impact to customer information stored outside of GitHub’s internal repositories, such as our customer’s own enterprises, organizations, and repositories. Some of GitHub’s internal repositories contain information from customers, for example, excerpts of support interactions. If any impact is discovered, we will notify customers via established incident response and notification channels.
We moved quickly to reduce risk. We rotated critical secrets Monday and into Tuesday with the highest-impact credentials prioritized first.
We continue to analyze logs, validate secret rotation, and monitor our infrastructure for any follow-on activity. We will take additional action as the investigation warrants.
We will publish a fuller report once the investigation is complete.
The post Investigation update: GitHub Enterprise Server signing key rotation appeared first on The GitHub Blog.
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