CVE-2026-1999

mediumpriority · track · 36OT risk · elevatedEPSS 0.004 · 30 %ileexploit · PoCDEEUNLUS
grimoire priorityP1 · Urgent
Exploitable?
Public exploit
2 exploits · PoC
Likely / severe?
0.36% (30th) EPSS
CVSS 6.5 · medium
Is it mine?
14 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · cert_bund · ncsc_nl

EPSS · scored 2026-10-27

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

7.1
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.7–7.1

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 3.6
v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:Nsecondary · NCSC-NL NL
v4.07.1highCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:L/SI:H/SA:Nsecondary · ENISA EU
v4.07.1highCVSS: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:Xsecondary · product-cna@github.com
v4.05.7mediumCVSS: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:P/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:Xsecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-863USCWE-863US
04

exploits (2)

Public proof-of-concept and weaponised exploit code.

05

affected products (14)

Products and version ranges known to be affected.

06

advisories (2)

Vendor and ecosystem advisories describing this.

  • NCSC-2026-0067Kwetsbaarheden verholpen in GitHub Enterprise ServerNL2026-02-20csaf · ncsc_nlNL

    GitHub heeft kwetsbaarheden verholpen in GitHub Enterprise Server (Specifiek voor versies vóór 3.20, 3.19.2, 3.18.5 en 3.17.11).

  • WID-SEC-W-2026-0460Microsoft GitHub Enterprise Server: Mehrere Schwachstellen ermöglichen Umgehen von SicherheitsvorkehrungenDeutsch2026-02-18csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Microsoft GitHub Enterprise Server ausnutzen, um Sicherheitsvorkehrungen zu umgehen.

07

also known as (3)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdcert_bundncsc_nlnvdNVDCVE.orgMITRE
published 2026-02-18modified 2026-06-17
09

references (15)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan