CVE-2026-9132

Missing authorization vulnerability in GitHub Enterprise Server allowed disclosure of private repository contents via the Copilot pull request diff summary endpoint

MEDIUM
6.5
CVSS Score
Published: June 30, 2026 at 08:23 PM UTC
Updated: October 25, 2026 at 09:10 PM UTC
1 product affected across 1 vendorGitHub Enterprise Server

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user to read source code from private repositories they did not have access to. The Copilot pull request description diff summary endpoint accepted a cross-repository comparison range and rendered the resulting diff without verifying that the requesting user was authorized to view the target repository. Exploitation required an authenticated account on the instance with read access to at least one repository to use as the comparison base. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.17.17, 3.18.11, 3.19.8, and 3.20.4. This vulnerability was reported via the GitHub Bug Bounty program.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.17.173.18.0 ≤ v < 3.18.113.19.0 ≤ v < 3.19.83.20.0 ≤ v < 3.20.43.17.03.18.03.19.03.20.0
Affected range stops below 3.17.17, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.18.11, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.19.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.20.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-862

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