What’s Vulnerable › Vulnerabilities

CVE-2026-54399: Apache HttpComponents Core: Unbounded HTTP Header/Line Length in Default Configuration

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-01 · updated 2026-10-25
• Weakness: CWE-400

Description

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 products

• Apache Software Foundation Apache HttpComponents Core: from 5.0 through 5.4.2; 5.5-alpha1, 5.5-beta1

References

• https://lists.apache.org/thread/zmxh1pl2zohov5ntdh4lt85gfrlchgpy
• http://www.openwall.com/lists/oss-security/2026/07/01/4

Get alerted when CVE-2026-54399 or the next vulnerability affects your stack