Auth bypass in GitHub Enterprise Server

CVE-2026-3306

An improper authorization vulnerability was identified in GitHub Enterprise Server that allowed a user with read access to a repository and write access to a project to modify issue and pull request metadata through the project. When adding an item to a project that already existed, column value updates were applied without verifying the actor's repository write permissions. This vulnerability was reported via the GitHub Bug Bounty program and has been fixed in GitHub Enterprise Server versions 3.14.24, 3.15.19, 3.16.15, 3.17.12, 3.18.6 and 3.19.3.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (34.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 34.5% 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-2026-3306: held from 0.004 to 0.004.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.001

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-3306?
CVE-2026-3306 is a medium-severity vulnerability in GitHub Enterprise Server, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2026-03-10.
How severe is CVE-2026-3306?
Medium severity. CVSS v3 base score is 4.3 out of 10.
Is CVE-2026-3306 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.