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.
History

Wed, 02 Sep 2026 10:45:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 01 Sep 2026 23:45:00 +0000

Type Values Removed Values Added
First Time appeared Github
Github enterprise Server
Vendors & Products Github
Github enterprise Server

Tue, 01 Sep 2026 22:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Server-side request forgery vulnerability in GitHub Enterprise Server Manage API leaked a replayable gateway-agent bearer token
Weaknesses CWE-918
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_P

Published: 2026-09-01T21:54:58.397Z

Updated: 2026-09-02T13:19:21.618Z

Reserved: 2026-08-03T18:33:43.917Z

Link: CVE-2026-18730

cve-icon Vulnrichment

Updated: 2026-09-02T13:19:17.995Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-01T22:17:10.850

Modified: 2026-09-03T16:43:15.293

Link: CVE-2026-18730

cve-icon Redhat

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