Github
CVE-2026-1999
HIGH
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate as user with webhook permissions
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ExploitConfigure webhook with internal loopback URL
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ExecutionTrigger webhook execution
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ImpactAccess internal services and administrative endpoints
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V4 - API and Web Service URL allowlisting, SSRF prevention
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Credential Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | GitHub Enterprise Server versions prior to 3.20 with authenticated user possessing webhook configuration permissions (repository admin, organization admin, or GitHub App administrator role). |
| Impact | CVSS 6.5 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: Low. User interaction: None. Exploitation requires authentication. |
| Exploit ScenarioDerived | An attacker (requires authentication) could exploit this vulnerability to compromise the affected system. |
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Alert meAnalysisAIv1 – Mar 12, 2026
GitHub Enterprise Server allows authenticated webhook administrators to bypass network restrictions through Server-Side Request Forgery, enabling access to internal services, job queues, and sensitive endpoints on loopback addresses. This affects all versions prior to 3.20 and requires valid credentials with webhook configuration privileges. No patch is currently available, and exploitation could lead to unauthorized data access or disruption of background job processing.
Earlier versions of this analysis (1)
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. [CVSS 6.5 MEDIUM]
RemediationAI
Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-918 (Server-Side Request Forgery (SSRF)). Affects Enterprise Server. 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
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:L/SI:H/SA:N
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
DescriptionGitHub Advisory
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.
Executive ViewAI
CVE-2026-1999 presents notable security risk, a server-side request forgery vulnerability rated CVSS 6.5. Users could be tricked into performing unintended actions. Organizations should apply vendor updates when available and monitor for exploitation.
Apply vendor patch. If patching is delayed: implement egress filtering, block metadata endpoints.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Server-Side Request Forgery exploits applications that fetch remote resources based on user-supplied URLs.
Affected Products (CPE)GitHub Advisory
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