What is CVE-2026-1699?

CVE-2026-1699 is a critical-severity vulnerability in Eclipse Theia Website, classified under Inclusion of Functionality from Untrusted Control Sphere. CVSS score: 10.0/10. Published 2026-01-30.

How severe is CVE-2026-1699?

Critical severity. CVSS v3 base score is 10.0 out of 10.

Vulnerability in Eclipse Theia Website

CVE-2026-1699

In the Eclipse Theia Website repository, the GitHub Actions workflow .github/workflows/preview.yml used pull_request_target trigger while checking out and executing untrusted pull request code. This allowed any GitHub user to execute arbitrary code in the repository's CI environment with access to repository secrets and a GITHUB_TOKEN with extensive write permissions (contents:write, packages:write, pages:write, actions:write). An attacker could exfiltrate secrets, publish malicious packages to the eclipse-theia organization, modify the official Theia website, and push malicious code to the repository.

EPSS: 0.005 (40.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Eclipse Theia_website
Eclipse Foundation Theia - Website — versions 0

Weakness classification (CWE)

CWE-829 — Inclusion of Functionality from Untrusted Control Sphere

References

emo@eclipse.org (Exploit, Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2026-1699?: CVE-2026-1699 is a critical-severity vulnerability in Eclipse Theia Website, classified under Inclusion of Functionality from Untrusted Control Sphere. CVSS score: 10.0/10. Published 2026-01-30.
How severe is CVE-2026-1699?: Critical severity. CVSS v3 base score is 10.0 out of 10.