CVE-2026-75101
CVE-2026-75101 — Authorization bypass vulnerability in GitHub Enterprise Server allowed reading of private pull request diffs and patches via repository name collision
An authorization bypass vulnerability was identified in GitHub Enterprise Server that allowed any authenticated user of the instance to read the raw diff or patch of pull requests in private repositories without authorization. Access tokens for raw pull request diffs and patches were scoped to the repository name and pull request number rather than to a globally unique repository identifier, so an attacker who created a repository and pull request matching a target's repository name and pull request number could use a token for their own repository to retrieve the private pull request's contents. Exploitation required the attacker to know the target repository's name and a valid pull request number. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.21, 3.18.15, 3.19.12, 3.20.8, and 3.21.6. This vulnerability was reported via the GitHub Bug Bounty program.
Published Updated Sources: NVD, GitHub (CNA), GitHub, GitHub Security Advisory
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
Not scored
FIRST has not published a score
CVSS base
6
medium
Remediation
The vendor's own words where we have them.
Upgrade Enterprise Server to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Prioritize based on EPSS, PoC availability, and external exposure.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| GitHub | Enterprise Server | 3.17.0 to < 3.17.* | Vulnerable |
| GitHub | Enterprise Server | 3.18.0 to < 3.18.* | Vulnerable |
| GitHub | Enterprise Server | 3.19.0 to < 3.19.* | Vulnerable |
| GitHub | Enterprise Server | 3.20.0 to < 3.20.* | Vulnerable |
| GitHub | Enterprise Server | 3.21.0 to < 3.21.* | Vulnerable |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Attack Complexity
Low
Attack Vector
Network
Privileges Req
Low
User Interaction
None
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 6 | CVSS 4.0 | medium | — | — | GitHub (CNA) |
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness & attack patterns
- CWE-639
Inferred from the weakness class — not observed against this CVE.
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Prioritize edge telemetry for network-reachable Enterprise Server.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added · CVSS 3.1 6.0 (AV:N)
Sep 22, 2026 · NVD
Initial · CVE published
Sep 22, 2026 · NVD
Added · GHSA-843p-hf47-6r9f published (medium)
Sep 22, 2026 · GitHub Security Advisory
References
7 on the record
- docs.github.com/en/[email protected]/admin/release-notes#3.17.21
Exploit, Third Party Advisory
- docs.github.com/en/[email protected]/admin/release-notes#3.18.15
Exploit, Third Party Advisory
- docs.github.com/en/[email protected]/admin/release-notes#3.19.12
Exploit, Third Party Advisory
- docs.github.com/en/[email protected]/admin/release-notes#3.20.8
Exploit, Third Party Advisory
- docs.github.com/en/[email protected]/admin/release-notes#3.21.6
Exploit, Third Party Advisory
- nvd.nist.gov/vuln/detail/CVE-2026-75101
NVD
- github.com/advisories/GHSA-843p-hf47-6r9f
Exploit, Third Party Advisory
Elsewhere on this site
- GitHubevery CVE for this vendor
- Access Controlsame class
- CWE-639other pages naming this weakness
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2026-75101 is Authorization bypass vulnerability in GitHub Enterprise Server allowed reading of private pull request diffs and patches via repository name collision, a medium vulnerability affecting Enterprise Server from GitHub. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-75101. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-75101. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 6 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.