Auth bypass in Google Cloud Build

CVE-2026-3136

An improper authorization vulnerability in GitHub Trigger Comment Control in Google Cloud Build prior to 2026-1-26 allows a remote attacker to execute arbitrary code in the build environment. This vulnerability was patched on 26 January 2026, and no customer action is needed.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (31.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 31.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-3136: held from 0.004 to 0.004.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-3136?
CVE-2026-3136 is a critical-severity vulnerability in Google Cloud Build, classified under Incorrect Authorization. CVSS score: 9.8/10. Published 2026-03-03.
How severe is CVE-2026-3136?
Critical severity. CVSS v3 base score is 9.8 out of 10.