CVE-2025-47287: Tornado is a Python web framework and asynchronous networking library

Q: How do I fix CVE-2025-47287?

tornado: upgrade to 6.5.0; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2025-47287 being exploited?

CVE-2025-47287 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-47287 affect?

CVE-2025-47287 affects tornado, debian linux. Severity is high (CVSS 7.5). 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 at

Q: How urgent is CVE-2025-47287?

Priority 50/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2025-47287 is a high-severity flaw (CVSS 7.5) affecting tornado, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 45%)
CISA exploited list	No
Weakness	CWE-770
Published	2025-05-15
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: debian · tornadoweb

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-05-15 22:15 UTCPublished CVE record published
2026-06-17 09:27 UTCUpdated Record last modified

tornadoweb tornado UPGRADE

Affected: < 6.5.0

Fixed in: 6.5.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy tornado || rpm -q tornado || tornado --version

2. UPGRADE to 6.5.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tornado

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tornado

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-47287?

tornado: upgrade to 6.5.0; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-47287 being exploited?

CVE-2025-47287 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-47287 affect?

CVE-2025-47287 affects tornado, debian linux. Severity is high (CVSS 7.5). 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 at

How urgent is CVE-2025-47287?

Priority 50/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Python vulnerabilities · Debian vulnerabilities

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References

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