Authentication bypass vulnerability in GitHub Enterprise Server allowed creation of local user accounts bypassing the configured external identity provider
An authentication bypass vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account, bypassing the configured external identity provider. When external authentication was enabled, the signup endpoint did not properly enforce the authentication restriction, allowing account creation and session establishment without identity provider validation. The created account was limited to the default base permissions configured on the instance. Exploitation required network access to a GHES instance configured with an external authentication provider. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.2, 3.19.6, 3.18.9, 3.17.15, and 3.16.18.
- Published
- May 7, 2026
- Updated
- Jun 17, 2026
- EPSS
- 0.4% · 33th percentile
- CWE
- CWE-306
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Report tools
Action score
25
Monitor
Low priority for now.
- CVSS
- 25 / 40 · 6.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.4%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_P
- 6.3
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| github | enterprise server | cpe:2.3:a:github:enterprise_server |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- github enterprise serverbefore 3.16.18
- github enterprise server3.17.0 and later · before 3.17.15
- github enterprise server3.18.0 and later · before 3.18.9
- github enterprise server3.19.0 and later · before 3.19.6
- github enterprise server3.20.0 and later · before 3.20.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_P). Independent of NVD's CPE analysis and usually ahead of it.
GitHub Enterprise Server
- 3.16.0 and later · up to and including 3.16.17affected · semverfixed in 3.16.18
- 3.17.0 and later · up to and including 3.17.14affected · semverfixed in 3.17.15
- 3.18.0 and later · up to and including 3.18.8affected · semverfixed in 3.18.9
- 3.19.0 and later · up to and including 3.19.5affected · semverfixed in 3.19.6
- 3.20.0 and later · up to and including 3.20.1affected · semverfixed in 3.20.2
Same product
github: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-0200Unsafe Reflection in Github Enterprise Server leading to Command Injection61This week
- CVE-2024-0507Privilege Escalation by Code Injection in the Management Console in GitHub Enterprise Server55Plan
- CVE-2024-9487An Improper Verification of Cryptographic Signature vulnerability was identified in GitHub Enterprise Server that allowed SAML SSO authentication to be bypassed46Plan
- CVE-2024-4985An authentication bypass vulnerability was present in the GitHub Enterprise Server (GHES) when utilizing SAML single sign-on authentication 41Plan
- CVE-2022-23739Incorrect authorization check in GitHub Enterprise Server leading to escalation of privileges in GraphQL API requests from GitHub Apps using scoped user-to-serv39Monitor
- CVE-2022-46255Improper Limitation of a Pathname to a Restricted Directory in GitHub Enterprise Server leading to RCE39Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| GitHub Enterprise Server | 3.16.18 | Vendor (CNA) |
| GitHub Enterprise Server | 3.17.15 | Vendor (CNA) |
| GitHub Enterprise Server | 3.18.9 | Vendor (CNA) |
| GitHub Enterprise Server | 3.19.6 | Vendor (CNA) |
| GitHub Enterprise Server | 3.20.2 | Vendor (CNA) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
—
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
- CVE-2026-385458 days apartRemote code execution via git push option injection in GitHub Enterprise Server34Monitor
- CVE-2026-1534371 days apartPath traversal vulnerability in GitHub Enterprise Server allowed writing files to arbitrary repository paths, including GitHub Actions workflow files, via unche34Monitor
- CVE-2026-226658 days apartImproper neutralization of input vulnerability was identified in GitHub Enterprise Server that allowed cross-site scripting via task list content and enabled ar29Monitor
- CVE-2026-1058554 days apartStored cross-site scripting vulnerability in GitHub Enterprise Server allowed arbitrary JavaScript execution via crafted Discussion titles in the Q&A category25Monitor
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-306 · Missing Authentication for Critical FunctionCVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Root cause
A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”
The bug in code
The whole CWE-306 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
// Added for the support teamapp.post("/maintenance/reset", resetDevice);Fixed
if (config.maintenanceEnabled) { app.post( "/maintenance/reset", requireSession, requireRole("admin"), resetDevice );}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18
- docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15
- docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9
- docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6
- docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2
Vendor advisories and official records. Exploit/PoC links are deliberately left out.