{"id":"CVE-2025-47287","aliases":["GHSA-7cx3-6m66-7c5m","PYSEC-2026-1974"],"title":"Tornado vulnerable to excessive logging caused by malformed multipart form data","summary":"Tornado vulnerable to excessive logging caused by malformed multipart form data","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"tornado","product":"tornado","ecosystem":"pip","affected":["tornado < 6.5"],"patched":["tornado 6.5"],"published":"2025-05-16","updated":"2026-09-10","sourceUpdated":"2026-09-10T03:50:24.284224963Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-7cx3-6m66-7c5m","references":[{"url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-7cx3-6m66-7c5m"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-47287"},{"url":"https://github.com/tornadoweb/tornado/commit/b39b892bf78fe8fea01dd45199aa88307e7162f3"},{"url":"https://github.com/tornadoweb/tornado"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00038.html"}],"tags":["osv","pip"],"epss":0.00741,"epssPercentile":0.53179,"ingestedAt":"2026-07-08T18:25:46.981Z","slug":"CVE-2025-47287","body":"## Overview\n\n### Summary\n\nWhen Tornado's ``multipart/form-data`` parser encounters certain errors, it logs a warning but continues trying to parse the remainder of the data. This allows remote attackers to generate an extremely high volume of logs, constituting a DoS attack. This DoS is compounded by the fact that the logging subsystem is synchronous.\n\n### Affected versions\n\nAll versions of Tornado prior to 6.5 are affected. The vulnerable parser is enabled by default.\n\n### Solution\n\nUpgrade to Tornado version 6.5. In the meantime, risk can be mitigated by blocking `Content-Type: multipart/form-data` in a proxy.\n\n## Affected packages\n\n- `tornado < 6.5`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `tornado 6.5`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}