CVE-2024-52804 | Tornado has HTTP cookie parsing DoS vulnerability

Tornado is a Python web framework and asynchronous networking library. 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. Version 6.4.2 fixes the issue.

Published: 2024-11-22 Last update: 2025-11-03 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-52804 is rated Moderate Risk (42.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.16%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-52804

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-05 0.15% 0.16% +0.01%
2 2026-05-06 0.16% 0.15% -0.01%
3 2026-05-02 — 0.16% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-52804

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2024-52804

GitHub Security Advisory for CVE-2024-52804

GHSA-8w49-h785-mj3c · Severity: high · Ecosystem: pip — Tornado has an HTTP cookie parsing DoS vulnerability

OS Trackers for CVE-2024-52804

vendor priority summary link
debian not yet assigned CVE-2024-52804 not yet assigned priority: Debian including 1 source packages (python-tornado), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2024-52804
redhat high — https://access.redhat.com/security/cve/CVE-2024-52804
suse medium CVE-2024-52804 severity moderate: SUSE including 16 source package names (latest:libsqlite3-0-3.49.1-slfo.1.1_1.1, libsqlite3-0-3.49.1-slfo.1.1_1.1, …), 93 product×package rows across 51 product lines (Container suse/sl-micro/6.0/baremetal-os-container, Container suse/sl-micro/6.0/base-os-container, … (51 product lines)): Will Not Fix 58, Fixed 30, Known Not Affected 5. https://www.suse.com/security/cve/CVE-2024-52804/
ubuntu medium CVE-2024-52804 medium priority: Ubuntu including 1 source packages (python-tornado), 9 status rows across 9 suites (bionic, focal, jammy, noble, oracular, plucky, questing, upstream, xenial): released 8, not-affected 1. https://ubuntu.com/security/CVE-2024-52804

Affected software / configurations for CVE-2024-52804

Vendor Product Version Raw CPE
tornadoweb tornado < 6.4.2 cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:*

References for CVE-2024-52804

cvelogic Threat Intelligence