CVE-2026-14340
An incorrect authorization vulnerability in GitHub Enterprise Server allows issue creation in unrelated public repositories
Description
An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed a user-to-server token scoped to a GitHub App installation to perform certain write operations on public repositories outside the token's intended scope. This was possible because the authorization check only verified that the installation had read permissions on the target repository rather than verifying that the token's installation was explicitly granted access to that repository. An attacker who obtained a victim's user-to-server token could create issues, issue comments, commit comments, and private vulnerability reports on any public repository, appearing as the victim user with no indication of the app involvement. This vulnerability was fixed by adding a repository scope check for user-to-server tokens issued by global apps. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.2, 3.20.4, 3.19.8, 3.18.11, 3.17.17, 3.16.20. This vulnerability was reported via the GitHub Bug Bounty program.
INFO
Published Date :
July 1, 2026, 9:16 p.m.
Last Modified :
Oct. 25, 2026, 4:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 82327ea3-741d-41e4-88f8-2cf9e791e760 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update GitHub Enterprise Server to version 3.21.2 or later.
- Apply security patches for affected versions.
- Review and restrict token scopes.
- Monitor repository access logs.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-14340.
| URL | Resource |
|---|---|
| https://docs.github.com/en/[email protected]/admin/release-notes#3.16.20 | Product Release Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.17.17 | Product Release Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.18.11 | Product Release Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.19.8 | Product Release Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.20.4 | Product Release Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.21.2 | Product Release Notes |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-14340 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-14340
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-14340 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-14340 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: Enterprise Server de GitHub, Description: Una vulnerabilidad de autorización incorrecta fue identificada en GitHub Enterprise Server que permitía que un token de usuario a servidor con alcance a una instalación de GitHub App realizara ciertas operaciones de escritura en repositorios públicos fuera del alcance previsto del token. Esto fue posible porque la verificación de autorización solo verificaba que la instalación tenía permisos de lectura en el repositorio de destino en lugar de verificar que a la instalación del token se le había concedido acceso explícitamente a ese repositorio. Un atacante que obtuviera un token de usuario a servidor de una víctima podría crear incidencias, comentarios de incidencias, comentarios de commits e informes de vulnerabilidad privados en cualquier repositorio público, apareciendo como el usuario víctima sin ninguna indicación de la participación de la aplicación. Esta vulnerabilidad fue corregida añadiendo una verificación de alcance de repositorio para tokens de usuario a servidor emitidos por aplicaciones globales. Esta vulnerabilidad afectó a todas las versiones de GitHub Enterprise Server anteriores a la 3.22 y fue corregida en las versiones 3.21.2, 3.20.4, 3.19.8, 3.18.11, 3.17.17, 3.16.20. Esta vulnerabilidad fue reportada a través del programa GitHub Bug Bounty. -
Initial Analysis by [email protected]
Jul. 06, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions up to (excluding) 3.16.20 *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions from (including) 3.17.0 up to (excluding) 3.17.17 *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions from (including) 3.18.0 up to (excluding) 3.18.11 *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions from (including) 3.19.0 up to (excluding) 3.19.8 *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions from (including) 3.20.0 up to (excluding) 3.20.4 *cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* versions from (including) 3.21.0 up to (excluding) 3.21.2 Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.16.20 Types: Product, Release Notes Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.17.17 Types: Product, Release Notes Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.18.11 Types: Product, Release Notes Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.19.8 Types: Product, Release Notes Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.20.4 Types: Product, Release Notes Added Reference Type GitHub, Inc. (Products Only): https://docs.github.com/en/[email protected]/admin/release-notes#3.21.2 Types: Product, Release Notes -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 02, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-14340', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-02T15:10:33.189761Z'} -
New CVE Received by [email protected]
Jul. 01, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'GitHub', 'product': 'Enterprise Server', 'versions': [{'status': 'affected', 'changes': [{'at': '3.16.20', 'status': 'unaffected'}], 'version': '3.16.0', 'versionType': 'semver', 'lessThanOrEqual': '3.16.19'}, {'status': 'affected', 'changes': [{'at': '3.17.17', 'status': 'unaffected'}], 'version': '3.17.0', 'versionType': 'semver', 'lessThanOrEqual': '3.17.16'}, {'status': 'affected', 'changes': [{'at': '3.18.11', 'status': 'unaffected'}], 'version': '3.18.0', 'versionType': 'semver', 'lessThanOrEqual': '3.18.10'}, {'status': 'affected', 'changes': [{'at': '3.19.8', 'status': 'unaffected'}], 'version': '3.19.0', 'versionType': 'semver', 'lessThanOrEqual': '3.19.7'}, {'status': 'affected', 'changes': [{'at': '3.20.4', 'status': 'unaffected'}], 'version': '3.20.0', 'versionType': 'semver', 'lessThanOrEqual': '3.20.3'}, {'status': 'affected', 'changes': [{'at': '3.21.2', 'status': 'unaffected'}], 'version': '3.21.0', 'versionType': 'semver', 'lessThanOrEqual': '3.21.1'}], 'platforms': ['Linux'], 'defaultStatus': 'affected'}] Added Description An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed a user-to-server token scoped to a GitHub App installation to perform certain write operations on public repositories outside the token's intended scope. This was possible because the authorization check only verified that the installation had read permissions on the target repository rather than verifying that the token's installation was explicitly granted access to that repository. An attacker who obtained a victim's user-to-server token could create issues, issue comments, commit comments, and private vulnerability reports on any public repository, appearing as the victim user with no indication of the app involvement. This vulnerability was fixed by adding a repository scope check for user-to-server tokens issued by global apps. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.2, 3.20.4, 3.19.8, 3.18.11, 3.17.17, 3.16.20. This vulnerability was reported via the GitHub Bug Bounty program. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-863 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.16.20 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.17.17 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.18.11 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.19.8 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.20.4 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.21.2