Resource exhaustion in Netty - #VU148879
Published: September 10, 2026
Vulnerability identifier: #VU148879
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in the HTTP/2 HpackEncoder when processing SETTINGS frames with a very large MAX_HEADER_TABLE_SIZE value. A remote attacker can send a SETTINGS frame with a large MAX_HEADER_TABLE_SIZE value to cause a denial of service.
The HPACK table is scoped to a connection.
Affected software
Netty
Remediation
Install security update from vendor's website.
Netty - addressed in versions 4.1.138, 4.2.18