Review reviewHigh

CVE-2026-11946

open62541 project / o6 Automation GmbH open62541

An unauthenticated remote attacker can exhaust server memory via the GetEndpoints Discovery Service in open62541. The endpointUrl field of GetEndpointsRequest is not validated for length. An attacker can declare an arbitrarily large string (up to ~4.09 GB via the UInt32 length field) 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 configurations. The issue affects open62541: from 1.4.0 through 1.4.16, from 1.5.0 through 1.5.4,...

CVSS: 7.5
EPSS: 0.38%
CISA KEV: Not listed
Published: 2026.07.02

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.38%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: open62541 project / o6 Automation GmbH open62541
Affected versions: 1.4.0, 1.5.0, master
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that open62541 project / o6 Automation GmbH open62541 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-770, CWE-789