CVE-2026-33592: FindServers Memory Exhaustion in open62541
An unauthenticated remote attacker can exhaust server memory via the FindServers Discovery Service in open62541. The serverUris field of FindServersRequest is not validated for length or array size. An attacker can declare an arbitrarily large string (up to ~3.9 GB) delivered across intermediate chunks without ever sending the final chunk. The server buffers all chunks in RAM indefinitely until the SecureChannel times out. The attack is pre-session and bypasses all encryption configuration. The issue affects open62541: from 1.4.0 through 1.4.16, from 1.5.0 through 1.5.4, master.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33592?
CVE-2026-33592 is rated as high severity with a score of 7.5.
What type of attack does CVE-2026-33592 enable?
CVE-2026-33592 allows unauthenticated remote attackers to exhaust server memory.
How does CVE-2026-33592 exploit the FindServers Discovery Service?
CVE-2026-33592 exploits the FindServers Discovery Service by sending a FindServersRequest with an unvalidated serverUris field.
What is the impact of CVE-2026-33592 on server availability?
The impact of CVE-2026-33592 is a denial of service condition due to memory exhaustion.
How do I mitigate CVE-2026-33592?
To mitigate CVE-2026-33592, validate the length and array size of the serverUris field in FindServersRequest.