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NVD / CVE Program· CNA GitHub_P

CVE-2026-1999: Incorrect Authorization vulnerability was identified in GitHub Enterprise Server that allowed unauthorized merging of pull requests

Noroxi assessment

Priority: Monitor (action score 28/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.36% (FIRST EPSS).
  • 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 Enterprise Server 3.17.11, 3.18.5, 3.19.2.

Low priority for now. Upgrade to GitHub Enterprise Server 3.17.11, 3.18.5, 3.19.2 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

An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to merge their own pull request into a repository without having push access by exploiting an authorization bypass in the enable_auto_merge mutation for pull requests. This issue only affected repositories that allow forking as the attack relies on opening a pull request from an attacker-controlled fork into the target repository. Exploitation was only possible in specific scenarios. It required a clean pull request status and only applied to branches without branch protection rules enabled. This vulnerability affected GitHub Enterprise Server versions prior to 3.19.2, 3.18.5, and 3.17.11, and was fixed in versions 3.19.2, 3.18.5, and 3.17.11. This vulnerability was reported via the GitHub Bug Bounty program.

HighCVSS 7.1 · v4.0—Proof of concept Fix available
Published
Feb 18, 2026
Updated
Jun 17, 2026
EPSS
0.3% · 29th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_P
7.1
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:L/SI:H/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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
githubenterprise 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 3.17.11
  • github enterprise server3.18.0 and later · before 3.18.5
  • github enterprise server3.19.0 and later · before 3.19.2

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

    • 3.17.0 and later · before 3.17.11affected · semverfixed in 3.17.11
    • 3.18.0 and later · before 3.18.5affected · semverfixed in 3.18.5
    • 3.19.0 and later · before 3.19.2affected · semverfixed in 3.19.2

Same product

github: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-0200Unsafe Reflection in Github Enterprise Server leading to Command Injection
    61This week
  • CVE-2024-0507Privilege Escalation by Code Injection in the Management Console in GitHub Enterprise Server
    55Plan
  • CVE-2026-3854Remote code execution via git push option injection in GitHub Enterprise Server
    46Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-0573Feb 18, 2026 · Improper Handling of HTTP Redirects vulnerability was identified in GitHub Enterprise Server that allowed leaking of authorization token and enabled remote code
    30Monitor
  • ← EarlierCVE-2026-1355Feb 18, 2026 · Missing Authorization Check in GitHub Enterprise Server Allows Unauthorized Uploads to Repository Migration Exports
    24Monitor
  • Later →CVE-2026-3306Mar 10, 2026 · Improper authorization in GitHub Projects allows modification of issue and pull request metadata without repository write access
    21Monitor

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 Enterprise Server3.17.11Vendor (CNA)
GitHub Enterprise Server3.18.5Vendor (CNA)
GitHub Enterprise Server3.19.2Vendor (CNA)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×2

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02026-03-15
Proof-of-concept repository on GitHubstars:02026-07-18

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.

  1. Published
  2. First PoC+24 d
  3. TodayOct 30, 2026+253 d

No history yet (it accumulates with the daily EPSS job).

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 researchers

Finders, 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.

  • CVE-2026-14340133 days apartAn incorrect authorization vulnerability in GitHub Enterprise Server allows issue creation in unrelated public repositories
    21Monitor
  • CVE-2025-6981218 days apartIncorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed unauthorized read-only access
    21Monitor

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
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:L/SI:H/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

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

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

All records