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VulnerabilityPublished

CVE-2026-8034: GitHub Enterprise Server · Server-Side Request Forgery (SSRF)

Affects GitHub Enterprise ServerSource CVE Database V5

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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

CVSS 4.0 base score
7.9High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
GitHubEnterprise ServerAffected
  • >=3.16.0 <3.16.18
  • >=3.17.0 <3.17.15
  • >=3.18.0 <3.18.9
  • >=3.19.0 <3.19.6
  • >=3.20.0 <3.20.2
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

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