Tensorlake reports malicious GitHub workflow runs after an upstream breach
Tensorlake says an attacker used engineering sandbox access to push malicious branch commits and trigger GitHub Actions to probe build and deployment secrets. The company removed the internal app, rotated secrets and asked customers to rotate their Tensorlake API keys as a precaution.
- Disclosed
- Nov 8, 2026
- Public disclosure date
- Severity
- Septic Tank Blew
- No CVE: a breach, not a bug
- Splash zone
- Tensorlake engineering repositories reachable from its internal automation sandboxes and the workflows triggered from those branches.
- Tensorlake · GitHub Actions · Secrets
- In the wild
- Yes
- Tensorlake confirms malicious pushes and workflow runs probing for secrets.
What happened
Tensorlake says an internal automation app running on an upstream provider started sandboxes under engineering team accounts. Those sandboxes had access to Tensorlake GitHub repositories. An attacker pushed malicious code to branches and triggered GitHub Actions to probe for build and deployment secrets. Tensorlake says it found no evidence of access to critical systems beyond the probing and reports that customer API keys and sandboxes were unaffected. The company has not published affected branch names, workflow identifiers or evidence that particular secrets were retrieved.
The founder’s initial public post named Railway as the app host. In the edited statement, Choudhury referred to an upstream provider and said a prior breach there had exposed environment variables that Tensorlake had left unrotated for the internal app. The follow-up also attributes the exposure to the upstream breach. The initial post and follow-up are available in the disclosure’s public copy and the reply’s public copy. A public copy of the edited statement preserves the later wording. The relationship to Railway’s October incident has not been independently verified. The earlier Tensorlake npm advisory covers a different event.
Tensorlake says it rotated its secrets and removed the app from the upstream host. It emailed paying customers and asked customers to rotate Tensorlake API keys as a precaution. Further details are expected by email and in the Tensorlake trust center.
Crime-scene timeline
Nov 8, 00:39 UTC
Tensorlake discloses unauthorized branch pushes and workflow runs
Founder Diptanu Choudhury says the company rotated its secrets, removed the internal app and notified paying customers by email. Customers are asked to rotate their API keys.
Nov 8, 01:44 UTC
Founder links the entry path to an upstream breach
In a follow-up, Choudhury attributes Tensorlake’s exposure to a provider breach.
Who said what
We list each claim and who made it. Primary sources (the vendor, the researcher, the registry) are marked. Where reports disagree, we grade by the worst credible case.
- Tensorlake founder’s disclosurePrimaryConfirms the repository and workflow activity, secret rotation, internal app removal and customer guidance.
- Tensorlake founder’s follow-upPrimaryAttributes exposure to an upstream provider breach.
- Tensorlake Cloud consolePrimaryOfficial entry point for Tensorlake customers.
- October Tensorlake npm advisoryPrimaryDocuments the separate October 8 malicious npm release.