Instituto Nacional de ciberseguridad. Sección Incibe
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CVE-2026-8106

Severity CVSS v4.0:
MEDIUM
Type:
CWE-79 Cross-Site Scripting (XSS)
Publication date:
07/05/2026
Last modified:
11/05/2026

Description

A reflected HTML injection vulnerability was identified in the GitHub Enterprise Server Management Console login page that could allow credential theft. The redirect_to query parameter on the /setup/unlock endpoint was reflected into an HTML attribute without proper sanitization, enabling an attacker to inject a form element that could capture administrator credentials. Exploitation required an administrator to click a crafted link and enter their credentials. This vulnerability affected GitHub Enterprise Server versions 3.19.1 through 3.19.5 and 3.20.0 through 3.20.1, and was fixed in versions 3.19.6 and 3.20.2. This vulnerability was reported via the GitHub Bug Bounty program.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 5.90 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

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

Base Score 4.0
5.90
Severity 4.0
MEDIUM
Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 6.10 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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

Base Score 3.x
6.10
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* 3.19.1 (including) 3.19.6 (excluding)
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* 3.20.0 (including) 3.20.2 (excluding)

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


References to Advisories, Solutions, and Tools