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Advisory record · GHSA-6hfq-h8hq-87mf

Multiple Transfer-Encoding headers misinterprets request payload

CVSS 4.8 MediumEPSS 0.048 · 91st percentile

Published by the GitHub Advisory Database at 5 Feb 2021, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
hypercrates.io>=0.12.0, <0.12.36 || >=0.13.0-0, <0.13.10 || >=0.14.0-0, <0.14.30.12.36, 0.13.10, 0.14.3
Identifiers
GHSA-6hfq-h8hq-87mf · CVE-2021-21299 · RUSTSEC-2021-0020
Weakness (CWE)
CWE-444
Tags
Published
5 Feb 2021
Updated
12 Oct 2026

Machine-written summary

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

The hyper crate, versions 0.12.0 up to 0.12.36, 0.13.0 up to 0.13.10, and 0.14.0 up to 0.14.3, can misread requests that carry multiple Transfer-Encoding headers as chunked, when such requests should be rejected. An attacker who can send requests through an upstream HTTP proxy that parses request boundaries differently may be able to smuggle requests or cause a desync. Upgrade hyper to 0.12.36, 0.13.10, or 0.14.3 or later.

Written 3 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
4.8 Medium 3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.048, the 91st percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:24 UTC First seen by agentprime
  2. 31 Oct 2026, 14:24 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.