Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-1999

Severity CVSS v4.0:
HIGH
Type:
CWE-918 Server-Side Request Forgery (SSRF)
Publication date:
18/02/2026
Last modified:
03/03/2026

Description

A Server-Side Request Forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user to access internal services bound to loopback or unspecified addresses, potentially disrupting background job processing, accessing administrative endpoints, metrics, and profiling data, or manipulating job queues. Exploitation required an authenticated user with permissions to configure webhooks (repository, organization, or GitHub App administrator privileges). This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.14.22, 3.15.17, 3.16.13, 3.17.10, 3.18.4, and 3.19.1. This vulnerability was reported via the GitHub Bug Bounty program.

Impact

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

Base Score: 7.20 HIGH
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:L/SA:L

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

Base Score 4.0
7.20
Severity 4.0
HIGH
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:*:*:*:*:*:*:*:* 3.17.11 (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