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.
References (3)
Core 3
Core References
Patch patch
https://github.com/open62541/open62541/pull/8142
Patch patch
https://github.com/open62541/open62541/pull/8142/changes/d253818d6c5e870e1db0e360b18138c8bdc809ae
Product product
https://github.com/open62541/open62541
Scores
CVSS v3
7.5
EPSS
0.0038
EPSS Percentile
30.9%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-770
CWE-789
Status
published
Products (3)
open62541 project / o6 Automation GmbH/open62541
1.4.0 - 1.4.16
open62541 project / o6 Automation GmbH/open62541
1.5.0 - 1.5.4
open62541 project / o6 Automation GmbH/open62541
master
Published
Jul 02, 2026
Tracked Since
Jul 02, 2026