Improper access control in GitHub Enterprise Server leading to the enumeration of private repository names
An improper access control vulnerability was identified in GitHub Enterprise Server that allowed authenticated users of the instance to determine the names of unauthorized private repositories given their numerical IDs. This vulnerability did not allow unauthorized access to any repository content besides the name. This vulnerability affected all versions of GitHub Enterprise Server prior to 2.22 and was fixed in versions 2.21.6, 2.20.15, and 2.19.21. This vulnerability was reported via the GitHub Bug Bounty program.
- Published
- Aug 27, 2020
- Updated
- Jun 16, 2026
- EPSS
- 1.1% · 63th percentile
- CWE
- CWE-285
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
17
Monitor
Low priority for now.
- CVSS
- 17 / 40 · 4.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.1%
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; 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 helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| github | github | cpe:2.3:a:github:github |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- github githubbefore 2.19.21
- github github2.20.0 and later · before 2.20.15
- github github2.21.0 and later · before 2.21.6
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 GitHub Enterprise Server
- 2.21 and later · before 2.21.6affected
- 2.20 and later · before 2.20.15affected
- 2.19 and later · before 2.19.21affected
Same product
github: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-18365The Management Console in GitHub Enterprise 2.8.x before 2.8.7 has a deserialization issue that allows unauthenticated remote attackers to e45Plan
- CVE-2020-10516Improper access control in GitHub Enterprise Server leading to privilege escalation of organization member39Monitor
- CVE-2020-10519Unsafe configuration options in GitHub Pages leading to remote code execution on GitHub Enterprise Server36Monitor
- CVE-2020-10518Unsafe configuration options in GitHub Pages leading to remote code execution on GitHub Enterprise Server36Monitor
- CVE-2021-22863Improper access control in GitHub Enterprise Server leading to unauthorized changes to maintainer permissions on pull requests32Monitor
- CVE-2012-2055GitHub Enterprise before 20120304 does not properly restrict the use of a hash to provide values for a model's attributes, which allows remo31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
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.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
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.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-285 · Improper AuthorizationCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
nvd-primary
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)
- Accessing Functionality Not Properly Constrained by ACLsCAPEC-1likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Directory IndexingCAPEC-127likelihood: High · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
- Using Malicious FilesCAPEC-17likelihood: High · Very High
- Manipulating Opaque Client-based Data TokensCAPEC-39likelihood: High · Medium
- Bypassing ATA Password SecurityCAPEC-402
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
ATT&CK techniques
- Data from Local SystemT1005
- Query RegistryT1012
- File and Directory DiscoveryT1083
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Unsecured Credentials: Credentials in RegistryT1552.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Data Manipulation: Transmitted Data ManipulationT1565.002
- Hijack Execution Flow: Executable Installer File Permissions WeaknessT1574.005
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
- Hijack Execution Flow: ServicesFile Permissions WeaknessT1574.010
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- enterprise.github.com/releases/2.19.21/notes
- enterprise.github.com/releases/2.20.15/notes
- enterprise.github.com/releases/2.21.6/notes
Vendor advisories and official records. Exploit/PoC links are deliberately left out.