CVE-2026-33592

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.

Score

CVSS 3.1 7.5 High

Status

Awaiting Analysis - a6d3dc9e-0591-4a13-bce7-0f5b31ff6158

Published

2026-07-02

Last modified

2026-10-25

Weaknesses

CWE-770, CWE-789

Affected products

• Open62541 (Open62541 Project O6 Automation Gmbh)

References

• https://github.com/open62541/open62541/pull/8142
• https://github.com/open62541/open62541/pull/8142/changes/d253818d6c5e870e1db0e360b18138c8bdc809ae
• https://github.com/open62541/open62541