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.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade python3-tornadoUpgrade pcsUpgrade pcs-snmp | May 27, 2025 | May 15, 2025 |
| Amazon Linux Ami 2 | — | Upgrade python3-tornado-docUpgrade python-tornadoUpgrade python-tornado-docUpgrade python-tornado-debuginfoUpgrade python3-tornado-debuginfoUpgrade 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 python-tornadoUpgrade pcs-snmpUpgrade python-tornado-docUpgrade python3-tornadoUpgrade pcs | May 27, 2025 | May 15, 2025 |
| Redhat_linux | — | Upgrade python-tornado-debuginfoUpgrade python3-tornadoUpgrade python-tornado-docUpgrade pcs-snmpNo solution existsUpgrade python3-tornado-debuginfoUpgrade python-tornado-debugsourceUpgrade pcsUpgrade python-tornado | May 27, 2025 | May 15, 2025 |
| Rocky_linux | — | Upgrade pcsUpgrade python3-tornadoUpgrade python3-tornado-debuginfoUpgrade pcs-snmpUpgrade python-tornado-debugsource | Jul 31, 2025 | Jul 29, 2025 |
| Suse | — | Upgrade salt-syndicUpgrade python3-tornadoUpgrade python3-saltUpgrade salt-apiUpgrade salt-standalone-formulas-configurationUpgrade python3-salt-testsuiteUpgrade salt-cloudUpgrade salt-transactional-updateUpgrade salt-docUpgrade salt-bash-completionUpgrade salt-minionUpgrade python313-tornado6Upgrade salt-proxyUpgrade salt-masterUpgrade salt-sshUpgrade salt-fish-completionUpgrade python311-tornado6Upgrade salt-zsh-completionUpgrade salt | Dec 5, 2025 | Jun 1, 2025 |
| Ubuntu | — | Upgrade python3-tornado (Ubuntu Pro)Upgrade python3-tornado | 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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