Review reviewHigh

CVE-2026-54399

Apache Software Foundation Apache HttpComponents Core, httpcomponents core

Uncontrolled Resource Consumption vulnerability in the HTTP/1.1 message parser 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 messages with excessive number of headers / excessive header length

CVSS
7.5
EPSS
0.56%
43.6% percentile
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 probability0.56%
Technical severityCVSS 7.5

Vulnerability overview

Uncontrolled Resource Consumption vulnerability in the HTTP/1.1 message parser 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 messages with excessive number of headers / excessive header length

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. 1
    Identify

    Confirm that Apache Software Foundation Apache HttpComponents Core, httpcomponents core and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 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