CVE-2026-33592

FindServers Memory Exhaustion in open62541

Published Jul 2, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Open62541 Project / O6 Automation Gmbh
Open62541 Project / O6 Automation Gmbh open62541
Vendors & Products Open62541 Project / O6 Automation Gmbh
Open62541 Project / O6 Automation Gmbh open62541
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title FindServers Memory Exhaustion in open62541
Weaknesses CWE-770
CWE-789
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
ENISA
Published
Updated
Jul 2, 2026, 12:30 PM
Reserved
Mar 23, 2026, 12:53 PM
Status
Awaiting Analysis
Published
Jul 2, 2026, 8:16 AM
Modified
Oct 25, 2026, 9:10 PM