CVE-2021-22863Network attack vector

Head-branch access via unauthorized maintainer permission changes

Published Mar 3, 2021 · Updated Aug 3, 2024

Improper authorization in GitHub Enterprise Server allows remote authenticated users to gain access to pull-request head branches. The GraphQL API fails to verify authorization before changing a pull request's maintainer collaboration permission, exposing its head branch. Exploitation requires an account and a pull request opened on a repository the user maintains; disabled forking prevents the path, and branch protections block unreviewed merges.

CVSS severity8.1
High
EPSS probability0.97%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in GitHub Enterprise Server allows remote authenticated users to gain access to pull-request head branches. The GraphQL API fails to verify authorization before changing a pull request's maintainer collaboration permission, exposing its head branch. Exploitation requires an account and a pull request opened on a repository the user maintains; disabled forking prevents the path, and branch protections block unreviewed merges.

The record

CVE
CVE-2021-22863
Published
Mar 3, 2021
Updated
Aug 3, 2024
Vendor
Twitter
Product
GitHub Enterprise Server
Classifications
CWE-285, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.20 <2.20.24
  2. Affected versionversion=2.21 <2.21.15
  3. Affected versionversion=2.22 <2.22.7
  4. Affected versionversion=3.0 <3.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Twitter · GitHub Enterprise Serverversion=2.20 <2.20.24; version=2.21 <2.21.15; version=2.22 <2.22.7; version=3.0 <3.0.1

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
5.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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