CVE-2026-26204

# Proof of Concept (PoC) for CVE-2026-26204 # This script demonstrates how a malicious agent might inject a crafted alert. # Note: This requires local access and compromised privileges. import os def trigger_vulnerability(log_file_path): # Simulating a crafted alert that triggers integer underflow in GetAlertData. # The specific payload depends on the exact parsing logic leading to offset -1. # This is a conceptual representation. crafted_alert = "<crafted_alert_content_triggering_underflow>" try: # Write the malicious alert to the log file monitored by wazuh-logcollector with open(log_file_path, 'a') as f: f.write(crafted_alert + "\n") print(f"[+] Payload injected into {log_file_path}") print("[*] Waiting for wazuh-logcollector to process the file...") print("[!] If vulnerable, the service may crash due to heap corruption.") except Exception as e: print(f"[-] Error: {e}") # Example usage (path needs to be specific to the target environment) # trigger_vulnerability('/var/ossec/logs/alerts/alerts.log')

{"cve": {"id": "CVE-2026-26204", "sourceIdentifier": "[email protected]", "published": "2026-04-29T18:16:04.820", "lastModified": "2026-04-30T20:40:53.320", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Wazuh is a free and open source platform used for threat prevention, detection, and response. From version 1.0.0 to before version 4.14.4, a heap-based out-of-bounds WRITE occurs in GetAlertData, resulting in writing a NULL byte exactly 1 byte before the start of the buffer allocated by strdup. Due to unsigned integer underflow and pointer arithmetic wrapping, the write lands at offset -1 from the buffer, corrupting heap metadata. A malicious actor can potentially leverage this issue through a compromised agent to cause denial of service or heap corruption by injecting a specially crafted alert into the alerts log file monitored by wazuh-logcollector. This issue has been patched in version 4.14.4."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "baseScore": 4.4, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 0.8, "impactScore": 3.6}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-124"}, {"lang": "en", "value": "CWE-191"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:wazuh:wazuh:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.0.0", "versionEndExcluding": "4.14.4", "matchCriteriaId": "B5795082-289E-455E-B5BE-929CF35FB92A"}]}]}], "references": [{"url": "https://github.com/wazuh/wazuh/releases/tag/v4.14.4", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/wazuh/wazuh/security/advisories/GHSA-j4c7-hwjw-8857", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/wazuh/wazuh/security/advisories/GHSA-j4c7-hwjw-8857", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}