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Advisory record · GHSA-8c42-7qj2-3j46

Netty Vulnerable to Cache Poisoning and Information Disclosure via CORS Vary Header Overwrite

CVSS 6.5 MediumEPSS 0.0032 · 25th percentile

Published by the GitHub Advisory Database at 17 Aug 2026, 18:24 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
io.netty:netty-codec-httpMaven>=4.2.0.Final, <4.2.17.Final || <4.1.137.Final4.2.17.Final, 4.1.137.Final
Identifiers
GHSA-8c42-7qj2-3j46 · CVE-2026-59903
Weakness (CWE)
CWE-524
Tags
Published
17 Aug 2026
Updated
10 Sept 2026

Machine-written summary

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

Netty's netty-codec-http package, versions from 4.2.0.Final before 4.2.17.Final and from 4.1.0 before 4.1.137.Final, has a CorsHandler that overwrites any Vary header already set by the backend application, replacing it with Vary: origin. An attacker who can reach a caching proxy or CDN in front of an affected application may be able to retrieve another user's cached sensitive response. Upgrade to 4.2.17.Final or 4.1.137.Final.

Written 2 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
6.5 Medium 3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0032, the 25th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:16 UTC First seen by agentprime
  2. 31 Oct 2026, 14:16 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.