DEBIAN-CVE-2025-67726

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Source
https://security-tracker.debian.org/tracker/CVE-2025-67726
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-67726.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2025-67726
Upstream
Published
2025-12-12T07:15:44.920Z
Modified
2026-01-09T03:18:11.910379Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
[none]
Details

Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The _parseparam function in httputil.py is used to parse specific HTTP header values, such as those in multipart/form-data and repeatedly calls string.count() within a nested loop while processing quoted semicolons. If an attacker sends a request with a large number of maliciously crafted parameters in a Content-Disposition header, the server's CPU usage increases quadratically (O(n²)) during parsing. Due to Tornado's single event loop architecture, a single malicious request can cause the entire server to become unresponsive for an extended period. This issue is fixed in version 6.5.3.

References

Affected packages

Debian:11 / python-tornado

Package

Name
python-tornado
Purl
pkg:deb/debian/python-tornado?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

6.*

6.1.0-1
6.1.0-1+deb11u1
6.1.0-1+deb11u2
6.1.0-2
6.1.0-3
6.2.0-1
6.2.0-2
6.2.0-3
6.3.2-1
6.4.0-1
6.4.0-2
6.4.1-1
6.4.1-2
6.4.1-3
6.4.2-1
6.4.2-2
6.4.2-3
6.5.2-1
6.5.2-2
6.5.2-3
6.5.4-0.1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-67726.json"

Debian:12 / python-tornado

Package

Name
python-tornado
Purl
pkg:deb/debian/python-tornado?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

6.*

6.2.0-3
6.2.0-3+deb12u1
6.2.0-3+deb12u2
6.3.2-1
6.4.0-1
6.4.0-2
6.4.1-1
6.4.1-2
6.4.1-3
6.4.2-1
6.4.2-2
6.4.2-3
6.5.2-1
6.5.2-2
6.5.2-3
6.5.4-0.1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-67726.json"

Debian:13 / python-tornado

Package

Name
python-tornado
Purl
pkg:deb/debian/python-tornado?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

6.*

6.4.2-3
6.5.2-1
6.5.2-2
6.5.2-3
6.5.4-0.1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-67726.json"

Debian:14 / python-tornado

Package

Name
python-tornado
Purl
pkg:deb/debian/python-tornado?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.5.4-0.1

Affected versions

6.*

6.4.2-3
6.5.2-1
6.5.2-2
6.5.2-3

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-67726.json"