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CVE-2026-1355

Severity CVSS v4.0:
MEDIUM
Type:
Unavailable / Other
Publication date:
18/02/2026
Last modified:
19/02/2026

Description

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.

Impact

Vector 4.0
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 CVSS v4.0 Severity and Metrics:

Base Score: 6.00 MEDIUM
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

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): Low
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): High
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): Low

Base Score 4.0
6.00
Severity 4.0
MEDIUM
Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N CVSS v3.1 Severity and Metrics:

Base Score: 6.50 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): High
Availability (A): None

Base Score 3.x
6.50
Severity 3.x
MEDIUM

Vulnerable products and versions

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

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools