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 pcs-snmpUpgrade pcsUpgrade python3-tornado | May 27, 2025 | May 15, 2025 |
| Amazon Linux Ami 2 | — | Upgrade python-tornadoUpgrade python3-tornado-docUpgrade 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 pcsUpgrade python3-tornadoUpgrade pcs-snmpUpgrade python-tornado-docUpgrade python-tornado | May 27, 2025 | May 15, 2025 |
| Redhat_linux | — | No solution existsUpgrade python-tornado-debugsourceUpgrade python-tornadoUpgrade pcsUpgrade python3-tornado-debuginfoUpgrade python3-tornadoUpgrade pcs-snmpUpgrade python-tornado-debuginfoUpgrade python-tornado-doc | May 27, 2025 | May 15, 2025 |
| Rocky_linux | — | Upgrade python-tornado-debugsourceUpgrade pcs-snmpUpgrade python3-tornado-debuginfoUpgrade pcsUpgrade python3-tornado | Jul 31, 2025 | Jul 29, 2025 |
| Suse | — | Upgrade salt-docUpgrade salt-zsh-completionUpgrade salt-proxyUpgrade salt-minionUpgrade salt-masterUpgrade python313-tornado6Upgrade salt-fish-completionUpgrade salt-transactional-updateUpgrade salt-cloudUpgrade salt-bash-completionUpgrade python311-tornado6Upgrade saltUpgrade salt-sshUpgrade salt-syndicUpgrade salt-apiUpgrade python3-tornadoUpgrade python3-saltUpgrade python3-salt-testsuiteUpgrade salt-standalone-formulas-configuration | 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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