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Advisory record · GHSA-v3jc-474w-2wm6

Apache HttpComponents Core: HPackDecoder Unlimited Header List Size Before SETTINGS ACK

CVSS 7.5 HighEPSS 0.0087 · 59th percentile

Published by the GitHub Advisory Database at 1 Jul 2026, 18:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
org.apache.httpcomponents.core5:httpcore5-h2Maven<5.4.3 || >=5.5-alpha1, <5.5-beta25.4.3, 5.5-beta2
Identifiers
GHSA-v3jc-474w-2wm6 · CVE-2026-54428
Weakness (CWE)
CWE-400 · CWE-770
Tags
Published
1 Jul 2026
Updated
10 Sept 2026

Machine-written summary

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

Apache HttpComponents Core httpcore5-h2 versions before 5.4.3 and from 5.5-alpha1 up to but not including 5.5-beta2 are vulnerable. A remote attacker can send oversized compressed HTTP/2 header blocks before the SETTINGS acknowledgement, which prevents the configured header list size limit from applying and can exhaust memory, causing a denial of service. Upgrade to version 5.4.3 or 5.5-beta2.

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
7.5 High 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H GitHub Advisory Database
  • CISA KEV Not listed.
  • EPSS 0.0087, the 59th percentile, on 8 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.