A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed a repository collaborator with write access to delete the current default branch through the GraphQL API and cause an attacker-controlled branch to become the new default. In repositories that required pull-request review but did not restrict branch deletion, this bypassed the review requirement and caused fresh clones and default-branch API requests to use attacker-controlled content. This vulnerability affected supported GitHub Enterprise Server releases in the 3.18, 3.19, 3.20, 3.21, and 3.22 series and was fixed in versions 3.18.16, 3.19.13, 3.20.9, 3.21.7, and 3.22.2. This vulnerability was reported via the GitHub Bug Bounty program.
CVE-2026-103620
MEDIUMPre-NVD 6.06.0Trending — 3 sources updated this week
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 6.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
6.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 6.0Exploit: None knownExposed services: Not assessed
The CVE record names the fixed release — apply it.
- CVSS v3
- 6.0
- EG Score
- 6.0MEDIUMlow confidence
- EG Risk
- 27EG Risk 27/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity60% × 45%Exploitation0% × 40%Automatability0% × 15%CISA SSVC: Track at every mission impact level.Action: The CVE record names the fixed release. Apply it within your standard update timelines. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
CISA SSVCTrack at every mission impact level.
The CVE record names the fixed release. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
October 6, 2026
Last Modified
October 7, 2026
Advisory Details (5)
Auto-updated Oct 6, 2026Fix named in the CVE record.
generic
Release notes - GitHub Enterprise Server 3.22 Docs
https://docs.github.com/en/[email protected]/admin/release-notes#3.22.2generic
Release notes - GitHub Enterprise Server 3.21 Docs
https://docs.github.com/en/[email protected]/admin/release-notes#3.21.7generic
Release notes - GitHub Enterprise Server 3.20 Docs
https://docs.github.com/en/[email protected]/admin/release-notes#3.20.9generic
Release notes - GitHub Enterprise Server 3.19 Docs
https://docs.github.com/en/[email protected]/admin/release-notes#3.19.13generic
Release notes - GitHub Enterprise Server 3.18 Docs
https://docs.github.com/en/[email protected]/admin/release-notes#3.18.16Vendor Advisories for CVE-2026-103620(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 7× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-10-07 17:39 UTCEG score recompute
- 2026-10-07 17:39 UTCGHSA enrichment
- 2026-10-07 16:51 UTCEG score recompute
- 2026-10-07 16:51 UTCGHSA enrichment
- 2026-10-06 19:33 UTCEG score recompute
- 2026-10-06 19:02 UTCEG score recompute
- 2026-10-06 19:01 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-103620?
CVE-2026-103620 is a medium vulnerability published on October 6, 2026. A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed a repository collaborator with write access to delete the current default branch through the GraphQL API and cause an attacker-controlled branch to become the new default. In repositories that required…
When was CVE-2026-103620 disclosed?
CVE-2026-103620 was first published on October 6, 2026, with the most recent update on October 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-103620?
CVE-2026-103620 has a CVSS base score of 6.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-103620?
The CVE record for CVE-2026-103620 names the fix: "This vulnerability affected supported GitHub Enterprise Server releases in the 3.18, 3.19, 3.20, 3.21, and 3.22 series and was fixed in versions 3.18.16, 3.19.13, 3.20.9, 3.21.7, and 3.22.2." The vendor advisories EchelonGraph has for CVE-2026-103620 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-103620
Is Your Infrastructure Affected by CVE-2026-103620?
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