Review reviewHigh

CVE-2026-54428

Apache Software Foundation Apache HttpComponents Core, httpcomponents core

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
EPSS: 0.59%
CISA KEV: Not listed
Published: 2026.07.02

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.59%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: Apache Software Foundation Apache HttpComponents Core, httpcomponents core
Affected versions: >= 5.5-alpha <= 5.5-beta1, >= 5.0-alpha <= 5.4.2, >= 5.0 <= 5.4.2, 5.5
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Apache Software Foundation Apache HttpComponents Core, httpcomponents core and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-400, CWE-770