CVE-2026-15783
Missing Authorization vulnerability was identified in GitHub Enterprise Server that allowed reading private repository metadata via delegated bypass rule suites
Description
A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user with write access to any repository to read metadata from private repositories they did not have access to, including private repository owners and names, branch names, commit SHAs, commit messages, and the pushing actor. The delegated bypass endpoint resolved a rule suite directly from an attacker-supplied, encoded identifier without verifying that the requesting user could read the rule suite's repository, and because these identifiers are sequential an attacker could enumerate them across the instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.18, 3.18.12, 3.19.9, 3.20.5, and 3.21.3. This vulnerability was reported via the GitHub Bug Bounty program.
INFO
Published Date :
July 17, 2026, 4:17 p.m.
Last Modified :
Oct. 24, 2026, 8:10 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 4.0 | MEDIUM | 82327ea3-741d-41e4-88f8-2cf9e791e760 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update GitHub Enterprise Server to versions 3.17.18 or later.
- Update GitHub Enterprise Server to versions 3.18.12 or later.
- Update GitHub Enterprise Server to versions 3.19.9 or later.
- Update GitHub Enterprise Server to versions 3.20.5 or later.
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-2026-15783.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-15783 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-2026-15783
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-2026-15783 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-15783 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.
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CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Added Translation Title: Enterprise Server de GitHub, Description: Una vulnerabilidad de autorización faltante fue identificada en GitHub Enterprise Server que permitía a un usuario autenticado con acceso de escritura a cualquier repositorio leer metadatos de repositorios privados a los que no tenían acceso, incluyendo propietarios y nombres de repositorios privados, nombres de ramas, SHAs de commit, mensajes de commit y el actor que realizaba el push. El endpoint de bypass delegado resolvía una suite de reglas directamente desde un identificador codificado, proporcionado por el atacante, sin verificar que el usuario solicitante pudiera leer el repositorio de la suite de reglas, y debido a que estos identificadores son secuenciales, un atacante podría enumerarlos en toda la instancia. Esta vulnerabilidad afectó a todas las versiones de GitHub Enterprise Server anteriores a la 3.22 y fue corregida en las versiones 3.17.18, 3.18.12, 3.19.9, 3.20.5 y 3.21.3. Esta vulnerabilidad fue reportada a través del programa GitHub Bug Bounty. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-15783', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-17T16:54:15.772592Z'} -
New CVE Received by [email protected]
Jul. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'GitHub', 'product': 'Enterprise Server', 'versions': [{'status': 'affected', 'changes': [{'at': '3.17.18', 'status': 'unaffected'}], 'version': '3.17.0', 'versionType': 'semver', 'lessThanOrEqual': '3.17.17'}, {'status': 'affected', 'changes': [{'at': '3.18.12', 'status': 'unaffected'}], 'version': '3.18.0', 'versionType': 'semver', 'lessThanOrEqual': '3.18.11'}, {'status': 'affected', 'changes': [{'at': '3.19.9', 'status': 'unaffected'}], 'version': '3.19.0', 'versionType': 'semver', 'lessThanOrEqual': '3.19.8'}, {'status': 'affected', 'changes': [{'at': '3.20.5', 'status': 'unaffected'}], 'version': '3.20.0', 'versionType': 'semver', 'lessThanOrEqual': '3.20.4'}, {'status': 'affected', 'changes': [{'at': '3.21.3', 'status': 'unaffected'}], 'version': '3.21.0', 'versionType': 'semver', 'lessThanOrEqual': '3.21.2'}], 'defaultStatus': 'affected'}] Added Description A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user with write access to any repository to read metadata from private repositories they did not have access to, including private repository owners and names, branch names, commit SHAs, commit messages, and the pushing actor. The delegated bypass endpoint resolved a rule suite directly from an attacker-supplied, encoded identifier without verifying that the requesting user could read the rule suite's repository, and because these identifiers are sequential an attacker could enumerate them across the instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.18, 3.18.12, 3.19.9, 3.20.5, and 3.21.3. 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:L/VI:N/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-862 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.17.18 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.18.12 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.19.9 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.20.5 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.21.3