CVE-2026-1355 MEDIUM

CVE-2026-1355: Missing Authorization Check in GitHub Enterprise Server Allows Unauthorized Uploads to Repository Migration Exports

Vendor Github
Product Enterprise Server
Weakness CWE-862 · Missing authorization
Published February 18, 2026
Last update February 20, 2026

CVSS base score

6.0/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:L

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

February 18, 2026 CVE published
February 20, 2026 Record updated

Related vulnerabilities

04Related CVE