HIGH7.5
PYSEC-2026-1975
Tornado has an HTTP cookie parsing DoS vulnerability
Quick fix
PYSEC-2026-1975 — tornado: upgrade to the fixed version with the command below.
pip install --upgrade 'tornado>=6.4.2'Details
The algorithm used for parsing HTTP cookies in Tornado versions prior to 6.4.2 sometimes has quadratic complexity, leading to excessive CPU consumption when parsing maliciously-crafted cookie headers. This parsing occurs in the event loop thread and may block the processing of other requests.
See also CVE-2024-7592 for a similar vulnerability in cpython.
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/tornadoweb/tornado/security/advisories/GHSA-8w49-h785-mj3c[WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2024-52804[ADVISORY]
- https://github.com/tornadoweb/tornado/commit/d5ba4a1695fbf7c6a3e54313262639b198291533[WEB]
- https://github.com/tornadoweb/tornado[PACKAGE]
- https://lists.debian.org/debian-lts-announce/2025/01/msg00000.html[WEB]
- https://pypi.org/project/tornado[PACKAGE]
- https://github.com/advisories/GHSA-8w49-h785-mj3c[ADVISORY]