GitHub Enterprise Server SSRF in Manage API (pre-3.22)
CVE-2026-18730 Published on September 1, 2026

Server-side request forgery vulnerability in GitHub Enterprise Server Manage API leaked a replayable gateway-agent bearer token
A server-side request forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to cause the Manage API to send crafted outbound requests to an attacker-controlled host. An unauthenticated endpoint parsed an attacker-supplied cluster configuration and issued gateway-to-agent requests whose HMAC authenticated only a timestamp, not the request path or body. An attacker positioned to intercept the outbound request could capture this token and replay it against privileged management agent endpoints. High-availability deployments were not affected due to a topology restriction. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.19, 3.18.13, 3.19.10, 3.20.6, and 3.21.4. This vulnerability was reported via the GitHub Bug Bounty program.

NVD

Vulnerability Analysis

CVE-2026-18730 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE

Weakness Type

What is a SSRF Vulnerability?

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.

CVE-2026-18730 has been classified to as a SSRF vulnerability or weakness.


Products Associated with CVE-2026-18730

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github Enterprise Server
 

Affected Versions

GitHub Enterprise Server: