CVE-2026-33592 | An unauthenticated remote attacker can exhaust server memory… | CVSS 7.5 HIGH

Description

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.

Metadata

CVE ID: CVE-2026-33592
State: PUBLISHED
Assigner: ENISA
Reserved: 2026-03-23 12:53 UTC
Published: 2026-07-02 07:12 UTC
Last updated: 2026-07-02 07:12 UTC
Primary CWE: CWE-770
CWE-770 Allocation of resources without limits or throttling
Vendor / Product: open62541 project / o6 Automation GmbH / open62541
Sources: cve.org · NVD

Severity & Metrics

7.5 HIGH CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products (1)

Vendor	Product	Platform	Versions
open62541 project / o6 Automation GmbH	open62541	—	1.4.0 ≤ 1.4.16, 1.5.0 ≤ 1.5.4, master

Weakness (CWE)

CWE	Source	Description
CWE-770	cna	CWE-770 Allocation of resources without limits or throttling
CWE-789	cna	CWE-789 Memory allocation with excessive size value

CVSS scores (1)

Score	Severity	Version	Source	Vector
7.5	HIGH	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References (3)