Tornado is a Python web framework and asynchronous networking library. When 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. All versions of Tornado prior to 6.5.0 are affected. The vulnerable parser is enabled by default. Upgrade to Tornado version 6.50 to receive a patch. As a workaround, risk can be mitigated by blocking `Content-Type: multipart/form-data` in a proxy.
CVSS Details
- CVSS 3.1 Base Score: 7.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade python3-tornadoUpgrade pcs-snmpUpgrade pcs | May 27, 2025 | May 15, 2025 |
| Amazon Linux Ami 2 | — | Upgrade python-tornado-debuginfoUpgrade python-tornadoUpgrade python3-tornado-docUpgrade python3-tornado-debuginfoUpgrade python-tornado-docUpgrade python3-tornado | Jun 13, 2025 | May 15, 2025 |
| Amazon_linux_2023 | — | Upgrade python3-tornado-debuginfoUpgrade python-tornado-debugsourceUpgrade python-tornado-docUpgrade python3-tornado | Jun 11, 2025 | May 15, 2025 |
| Debian | — | Upgrade python-tornado | May 20, 2025 | May 15, 2025 |
| Oracle_linux | — | Upgrade pcs-snmpUpgrade python-tornado-docUpgrade python-tornadoUpgrade pcsUpgrade python3-tornado | May 27, 2025 | May 15, 2025 |
| Redhat_linux | — | Upgrade python3-tornado-debuginfoNo solution existsUpgrade python-tornado-debugsourceUpgrade python-tornadoUpgrade pcsUpgrade python3-tornadoUpgrade python-tornado-docUpgrade python-tornado-debuginfoUpgrade pcs-snmp | May 27, 2025 | May 15, 2025 |
| Rocky_linux | — | Upgrade pcs-snmpUpgrade python-tornado-debugsourceUpgrade python3-tornado-debuginfoUpgrade pcsUpgrade python3-tornado | Jul 31, 2025 | Jul 29, 2025 |
| Suse | — | Upgrade python3-tornadoUpgrade python3-salt-testsuiteUpgrade salt-apiUpgrade python3-saltUpgrade salt-syndicUpgrade salt-standalone-formulas-configurationUpgrade salt-zsh-completionUpgrade salt-fish-completionUpgrade salt-proxyUpgrade salt-sshUpgrade salt-transactional-updateUpgrade python313-tornado6Upgrade salt-minionUpgrade salt-masterUpgrade saltUpgrade python311-tornado6Upgrade salt-cloudUpgrade salt-bash-completionUpgrade salt-doc | Dec 5, 2025 | Jun 1, 2025 |
| Ubuntu | — | Upgrade python3-tornadoUpgrade python3-tornado (Ubuntu Pro) | Jun 4, 2025 | May 15, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Aug 20, 2025 | May 15, 2025 |
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