CVE-2026-35537

import requests import pickle # Conceptual PoC for CVE-2026-35537 # This demonstrates how an attacker might craft a session payload. # In a real scenario, the payload would target PHP serialization format specific to Roundcube. target_url = "http://target-host/" # Malicious payload simulation (PHP serialized payload for file write) # This is a placeholder representing the crafted object string malicious_payload = "O:8:"stdClass":0:{}" # Attacker sets the malicious cookie cookies = { "roundcube_sessid": "attacker_controlled_session_id", "roundcube_sessauth": malicious_payload } try: response = requests.get(target_url, cookies=cookies) if response.status_code == 200: print("[+] Payload sent successfully.") else: print("[-] Failed to send payload.") except Exception as e: print(f"[!] Error: {e}")

{"cve": {"id": "CVE-2026-35537", "sourceIdentifier": "[email protected]", "published": "2026-04-03T04:17:10.313", "lastModified": "2026-04-13T17:54:32.260", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Unsafe deserialization in the redis/memcache session handler may lead to arbitrary file write operations by unauthenticated attackers via crafted session data."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N", "baseScore": 3.7, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 1.4}, {"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:H/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-502"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.5.14", "matchCriteriaId": "40F75FD7-CF6D-4DC4-A33D-625D0F02FAB3"}, {"vulnerable": true, "criteria": "cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.6.0", "versionEndExcluding": "1.6.14", "matchCriteriaId": "AF4B6448-D4F5-4680-B32C-9366630E9485"}]}]}], "references": [{"url": "https://github.com/roundcube/roundcubemail/commit/618c5428edc69fb088e7ac6c89e506dd39df3", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/roundcube/roundcubemail/commit/6d586cfa4d8a31f7957f7a445aaedd52592a0e74", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/roundcube/roundcubemail/commit/a4ead994d2f0ea92e4a1603196a197e0d5df1620", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/roundcube/roundcubemail/releases/tag/1.5.14", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/roundcube/roundcubemail/releases/tag/1.6.14", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/04/11/6", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Issue Tracking", "Mailing List"]}]}}