Apache HttpComponents 5.4.2-or-earlier: Resource Exhaustion via HTTP/1.1 parser
CVE-2026-54399 Published on July 1, 2026
Apache HttpComponents Core: Unbounded HTTP Header/Line Length in Default Configuration
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
Vulnerability Analysis
CVE-2026-54399 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Resource Exhaustion Vulnerability?
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
CVE-2026-54399 has been classified to as a Resource Exhaustion vulnerability or weakness.
Affected Versions
Apache Software Foundation Apache HttpComponents Core:- Version 5.5-alpha, <= 5.5-beta1 is affected.
- Version 5.0-alpha, <= 5.4.2 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.