CVE-2026-11946

Summary

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, master.

Affected Software

VendorProductVersion RangeStatus
open62541 project / o6 Automation GmbHopen625411.4.0 <= 1.4.16affected
open62541 project / o6 Automation GmbHopen625411.5.0 <= 1.5.4affected
open62541 project / o6 Automation GmbHopen62541masteraffected

Weaknesses

  • CWE-770: CWE-770 Allocation of resources without limits or throttling
  • CWE-789: CWE-789 Memory allocation with excessive size value

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References