CVE-2026-54428

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

Published Jul 1, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Allocation of resources without limits or throttling in the HTTP/2 HPACK decoder in Apache HttpComponents Core (5.4.2 and earlier, 5.5-beta1 and earlier) allows an remote attacker to cause a denial of service through memory exhaustion by sending oversized compressed header blocks before the HTTP/2 SETTINGS acknowledgement causes the configured header list size limit to be applied.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-v3jc-474w-2wm6 Apache HttpComponents Core: HPackDecoder Unlimited Header List Size Before SETTINGS ACK
History
Type Values Removed Values Added
First Time appeared Apache
Apache httpcomponents Core
Vendors & Products Apache
Apache httpcomponents Core
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Allocation of resources without limits or throttling in the HTTP/2 HPACK decoder in Apache HttpComponents Core (5.4.2 and earlier, 5.5-beta1 and earlier) allows an remote attacker to cause a denial of service through memory exhaustion by sending oversized compressed header blocks before the HTTP/2 SETTINGS acknowledgement causes the configured header list size limit to be applied.
Title Apache HttpComponents Core: HPackDecoder Unlimited Header List Size Before SETTINGS ACK
Weaknesses CWE-400
CWE-770
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Jul 1, 2026, 6:15 PM
Reserved
Jun 14, 2026, 9:39 AM
Status
Analyzed
Published
Jul 1, 2026, 6:16 PM
Modified
Oct 25, 2026, 5:10 PM
Severity
Important
Public date
Jul 1, 2026, 5:03 PM