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NVD / CVE Program· CNA GitHub_P

CVE-2020-10518: Unsafe configuration options in GitHub Pages leading to remote code execution on GitHub Enterprise Server

HighCVSS 8.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 3.6% (FIRST EPSS); higher than 89.8% of all records.
  • 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.
  • Fixed version: GitHub GitHub Enterprise Server 2.21.6.

Low priority for now. Upgrade to GitHub GitHub Enterprise Server 2.21.6 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A remote code execution vulnerability was identified in GitHub Enterprise Server that could be exploited when building a GitHub Pages site. User-controlled configuration of the underlying parsers used by GitHub Pages were not sufficiently restricted and made it possible to execute commands on the GitHub Enterprise Server instance. To exploit this vulnerability, an attacker would need permission to create and build a GitHub Pages site on the GitHub Enterprise Server instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 2.22 and was fixed in 2.21.6, 2.20.15, and 2.19.21. The underlying issues contributing to this vulnerability were identified both internally and through the GitHub Security Bug Bounty program.

Published
Aug 27, 2020
Updated
Jun 16, 2026
EPSS
3.6% · 89th percentile

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 3.6%

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  • Not in KEV: no record of exploitation in the wild
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
githubgithub

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

    • 2.19 and later · before 2.19.21affected
    • 2.20 and later · before 2.20.15affected
    • 2.21 and later · before 2.21.6affected

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

Same product

github: all records

Other 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…
    60This week
  • CVE-2020-10516Improper access control in GitHub Enterprise Server leading to privilege escalation of organization member
    39Monitor
  • CVE-2020-10519Unsafe configuration options in GitHub Pages leading to remote code execution on GitHub Enterprise Server
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2012-2055Apr 5, 2012 · GitHub Enterprise before 20120304 does not properly restrict the use of a hash to provide values for a model's attributes, which allows…
    31Monitor
  • ← EarlierCVE-2020-10517Aug 27, 2020 · Improper access control in GitHub Enterprise Server leading to the enumeration of private repository names
    17Monitor
  • Later →CVE-2021-22861Mar 3, 2021 · Improper access control in GitHub Enterprise Server leading to unauthorized write access to forkable repositories
    26Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
GitHub GitHub Enterprise Server2.21.6 · descriptionVendor (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.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: EPSS history · patch commit or PR link · variant or chain candidate.

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
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-77 · Improper Neutralization of Special Elements used in a Command ('Command Injection')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

ATT&CK techniques

—

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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