Auth bypass in GitHub

CVE-2021-22861

An improper access control vulnerability was identified in GitHub Enterprise Server that allowed authenticated users of the instance to gain write access to unauthorized repositories via specifically crafted pull requests and REST API requests. An attacker would need to be able to fork the targeted repository, a setting that is disabled by default for organization owned private repositories. Branch protections such as required pull request reviews or status checks would prevent unauthorized commits from being merged without further review or validation. This vulnerability affected all versions of GitHub Enterprise Server since 2.4.21 and was fixed in versions 2.20.24, 2.21.15, 2.22.7 and 3.0.1. This vulnerability was reported via the GitHub Bug Bounty program.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.010 (59.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 59.8% 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-2021-22861: held from 0.009 to 0.010.

EPSS over last 30 days · oldest: 0.009 · newest: 0.010 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-22861?
CVE-2021-22861 is a medium-severity vulnerability in GitHub, classified under Improper Authorization. CVSS score: 6.5/10. Published 2021-03-03.
How severe is CVE-2021-22861?
Medium severity. CVSS v3 base score is 6.5 out of 10.