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CVE-2026-1355

MEDIUM CVSS 4.0: 6.0 EPSS 0.16%
Updated Feb 19, 2026
GitHub
Parameter Value
CVSS 6.0 (MEDIUM)
Affected Versions 3.15.0 — 3.19.2
Fixed In 3.14.23
Type CWE-862 (Missing Authorization)
Vendor GitHub
Public PoC No

A Missing Authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to upload unauthorized content to another user’s repository migration export due to a missing authorization check in the repository migration upload endpoint. By supplying the migration identifier, an attacker could overwrite or replace a victim’s migration archive, potentially causing victims to download attacker-controlled repository data during migration restores or automated imports. An attacker would require authentication to the victim's GitHub Enterprise Server instance.

This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.19.2, 3.18.5, 3.17.11, 3.16.14, 3.15.18, 3.14.23. This vulnerability was reported via the GitHub Bug Bounty program.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
High
Complete data modification
Availability
None
No disruption

CVSS Vector v4.0

Vulnerable Products 6

Configuration From (including) Up to (excluding)
Github Enterprise_Server
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
3.14.23
Github Enterprise_Server
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
3.15.0 3.15.18
Github Enterprise_Server
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
3.16.0 3.16.14
Github Enterprise_Server
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
3.17.0 3.17.11
Github Enterprise_Server
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
3.18.0 3.18.5
Github Enterprise_Server
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
3.19.0 3.19.2