High 7.5Published Jul 1, 2026

CVE-2026-54428Apache HttpComponents Core: HPackDecoder Unlimited Header List Size Before SETTINGS ACK

Updated under an hour ago (Oct 28, 2026, 2:30 AM ET)

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It affects Apache Software Foundation Apache HttpComponents Core and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Apache Software Foundation Apache HttpComponents Core

Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-770, CWE-400
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: apache
NVD analysis: Analyzed
Record last updated: Jul 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Apache Software Foundation Apache HttpComponents Core apache_software_foundation:apache_httpcomponents_core (from the name)	from 5.5-alpha through 5.5-beta1; from 5.0-alpha through 5.4.2	CNA record
apache httpcomponents_core apache:httpcomponents_core	from 5.0 through 5.4.2; 5.5; 5.5	NVD

References

References

https://lists.apache.org/thread/5zjp8vczvxq19pw2rvhs21q446bhl0sd	vendor-advisory, mitigation
http://www.openwall.com/lists/oss-security/2026/07/01/3	mitigation, third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.