CVE-2026-8034: GitHub Enterprise Server · Server-Side Request Forgery (SSRF)
Affects GitHub Enterprise ServerSource CVE Database V5
Not known to be exploited · CVSS 7.9 High · fixed in 3.16.18 : patch GitHub Enterprise Server soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.16.18
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:HExploitation evidence
Disclosed: evidence found.
CVE published 7 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| GitHubEnterprise Server | Affected
| Fixed in– |
AI-suggested
This vulnerability has been fixed in GitHub Enterprise Server versions 3.16.18, 3.17.15, 3.18.9, 3.19.6, and 3.20.2. Users should upgrade affected GitHub Enterprise Server instances to one of these patched versions or later to remediate the issue. Since this is an on-premises product, the vendor does not manage patching directly. Patch status is confirmed by the vendor advisory embedded in the description.
Description
CVE-2026-8034 is a server-side request forgery (SSRF) vulnerability in the GitHub Enterprise Server notebook viewer. It arises from a discrepancy between the URL parser used for hostname validation and the one used by the HTTP request library, allowing crafted URLs to bypass validation and access unintended internal hosts. This vulnerability affects all GitHub Enterprise Server versions prior to 3.21 and requires network access to the server instance for exploitation. It has a high severity with a CVSS score of 7.9. Fixes were released in versions 3.16.18, 3.17.
References
- docs.github.com/en/enterprise-server@3.16/admin/release-notes (opens in a new tab)
- docs.github.com/en/enterprise-server@3.17/admin/release-notes (opens in a new tab)
- docs.github.com/en/enterprise-server@3.18/admin/release-notes (opens in a new tab)
- docs.github.com/en/enterprise-server@3.19/admin/release-notes (opens in a new tab)
- docs.github.com/en/enterprise-server@3.20/admin/release-notes (opens in a new tab)