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Advisory record · GHSA-qppv-j76h-2rpx

Tornado vulnerable to HTTP request smuggling via improper parsing of `Content-Length` fields and chunk lengths

CVSS 9.0 CriticalCriticalEPSS 0.0038 · 31st percentile

Critical, because:

  • CVSS score 9.0: 9.0 or more.

How we decide what’s critical

Published by the GitHub Advisory Database at 14 Aug 2023, 21:34 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
tornadoPyPI<6.3.36.3.3
Identifiers
GHSA-qppv-j76h-2rpx · CVE-2023-54397
Weakness (CWE)
CWE-444
Tags
Published
14 Aug 2023
Updated
16 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Tornado versions before 6.3.3 accept the characters "-", "+", and "_" in Content-Length and chunk length values, which HTTP does not allow. An attacker who can send crafted HTTP requests through a proxy that reads these characters differently could smuggle requests past it. The source notes this is known to affect older versions of haproxy and that the current release is not affected. Upgrade Tornado to version 6.3.3 or later.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
9.0 Critical 4.0 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N CNA (VulnCheck)
  • CISA KEV Not listed.
  • EPSS 0.0038, the 31st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:10 UTC First seen by agentprime
  2. 31 Oct 2026, 14:10 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.