CVE-2026-11946Network attack vector

Unauthenticated memory exhaustion via unbounded message buffering

Published Jul 2, 2026 · Updated Jul 2, 2026

Resource exhaustion in open62541 1.4.0 through 1.4.16 and 1.5.0 through 1.5.4 allows remote attackers to exhaust server memory. The binary server channel accepts a UInt32 endpointUrl length and retains incomplete GetEndpoints chunks without enforcing message or chunk limits. The pre-session path requires neither authentication nor encryption and interrupts service as memory is consumed; master is also affected.

CVSS severity7.5
High
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in open62541 1.4.0 through 1.4.16 and 1.5.0 through 1.5.4 allows remote attackers to exhaust server memory. The binary server channel accepts a UInt32 endpointUrl length and retains incomplete GetEndpoints chunks without enforcing message or chunk limits. The pre-session path requires neither authentication nor encryption and interrupts service as memory is consumed; master is also affected.

The record

CVE
CVE-2026-11946
Published
Jul 2, 2026
Updated
Jul 2, 2026
Vendor
o6 Automation GmbH
Product
open62541
Classifications
CWE-789, CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.4.0 <=1.4.16
  2. Affected versionversion=1.5.0 <=1.5.4
  3. Affected versionversion=master

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

o6 Automation GmbH · open62541version=1.4.0 <=1.4.16; version=1.5.0 <=1.5.4; version=master

Published CVSS scores

7.5ENISACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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