CVE-2025-47287
highpriority · track · 0EPSS 0.007 · 55 %ileDEEURUUSEPSS · scored 2026-10-26
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (26)
Products and version ranges known to be affected.
advisories (3)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2025-1143Red Hat Enterprise Linux (python-tornado): Schwachstelle ermöglicht Denial of ServiceDeutsch2025-05-25csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Red Hat Enterprise Linux ausnutzen, um einen Denial of Service Angriff durchzuführen.
- GHSA-7cx3-6m66-7c5mTornado vulnerable to excessive logging caused by malformed multipart form data2025-05-16ghsa · osvUS
### Summary 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. ### Affected versions All versions of Tornado prior to 6.5 are affected. The vulnerable parser is enabled by default. ### Solution Upgrade to Tornado version 6.5. In the meantime, risk can be mitigated by blocking `Content-Type: multipart/form-data` in a proxy.
- PYSEC-2026-1974Tornado vulnerable to excessive logging caused by malformed multipart form data2026-07-07vendor · osvUS
### Summary 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. ### Affected versions All versions of Tornado prior to 6.5 are affected. The vulnerable parser is enabled by default. ### Solution Upgrade to Tornado version 6.5. In the meantime, risk can be mitigated by blocking `Content-Type: multipart/form-data` in a proxy.
also known as (8)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (9)
External citations — patches, advisories, analysis.
- https://github.com/tornadoweb/tornado/commit/b39b892bf78fe8fea01dd45199aa88307e7162f3cnnvd
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-7cx3-6m66-7c5mcnnvd
- https://github.com/tornadoweb/tornado/tagsPatchcnnvd
- https://vigilance.fr/vulnerability/Tornado-overload-via-Malformed-multipart-form-data-47246cnnvd
- https://github.com/tornadoweb/tornado/commit/b39b892bf78fe8fea01dd45199aa88307e7162f3enisa_euvd
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-7cx3-6m66-7c5menisa_euvd
- https://github.com/tornadoweb/tornado/commit/b39b892bf78fe8fea01dd45199aa88307e7162f3Patchnvd
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-7cx3-6m66-7c5mVendor Advisorynvd
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