CVE-2026-54399 in Apache 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
Quick answer
Apache Software Foundation Apache HttpComponents Core should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Apache HttpComponents Core 5.4.2 and earlier
- Apache HttpComponents Core 5.5-beta1 and earlier
Fixed versions
- Apache HttpComponents Core 5.4.3 or 5.5-beta2 or later
How to fix it
CVE-2026-54399 affects Apache HttpComponents Core. In simple terms, an attacker may be able to make the service slow or stop if the affected part is exposed or receives unsafe input. Update to Apache HttpComponents Core 5.4.3 or 5.5-beta2 or later. If you cannot update now, limit access until the fix is installed.
- Find every Apache HttpComponents Core install and check its version.
- Update to Apache HttpComponents Core 5.4.3 or 5.5-beta2 or later.
- If you cannot update today, block public access to the risky feature or service.
- Review logs for strange access, crashes, deleted files, or failed requests.
- Rotate secrets if you think the issue may have been used.
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Verify the fix
- Confirm the installed version is fixed or the mitigation is active.
- Test the affected feature with a normal user account.
- Confirm untrusted users cannot reach the risky path or service.
- Run a fresh Fixnx scan and keep the result with your change record.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-54399?
Apache Software Foundation Apache HttpComponents Core versions listed as affected should be reviewed: Apache HttpComponents Core 5.4.2 and earlier, Apache HttpComponents Core 5.5-beta1 and earlier.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.