CVE-2025-67726

{"id": "CVE-2025-67726", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "published": "2025-12-12T07:15:44.920", "references": [{"url": "https://github.com/tornadoweb/tornado/commit/771472cfdaeebc0d89a9cc46e249f8891a6b29cd", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/tornadoweb/tornado/releases/tag/v6.5.3", "tags": ["Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-jhmp-mqwm-3gq8", "tags": ["Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-834"}]}], "descriptions": [{"lang": "en", "value": "Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The _parseparam function in httputil.py is used to parse specific HTTP header values, such as those in multipart/form-data and repeatedly calls string.count() within a nested loop while processing quoted semicolons. If an attacker sends a request with a large number of maliciously crafted parameters in a Content-Disposition header, the server's CPU usage increases quadratically (O(n\u00b2)) during parsing. Due to Tornado's single event loop architecture, a single malicious request can cause the entire server to become unresponsive for an extended period. This issue is fixed in version 6.5.3."}], "lastModified": "2025-12-22T18:56:47.850", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "64279E50-159B-4CAB-9BD0-E2B764C3C40C", "versionEndExcluding": "6.5.3"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}