CVE-2020-8867Known exploitationNetwork attack vector

Server crash via unlocked session operations

Published Apr 22, 2020 · Updated Aug 4, 2024

Race condition in OPC Foundation OPC UA .NET Standard Stack 1.04.358.30 allows remote attackers to crash OPC UA servers via session requests. The session-handling path operates on shared state without proper locking, allowing concurrent requests to corrupt processing state. No authentication is required; malformed network messages can terminate an affected server and interrupt OPC UA service.

CVSS severity7.5
High
EPSS probability2.64%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in OPC Foundation OPC UA .NET Standard Stack 1.04.358.30 allows remote attackers to crash OPC UA servers via session requests. The session-handling path operates on shared state without proper locking, allowing concurrent requests to corrupt processing state. No authentication is required; malformed network messages can terminate an affected server and interrupt OPC UA service.

The record

CVE
CVE-2020-8867
Published
Apr 22, 2020
Updated
Aug 4, 2024
Vendor
OPC Foundation
Product
OPC UA .NET Standard Stack
Classifications
CWE-613, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 22, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=1.04.358.30

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OPC Foundation · OPC UA .NET Standard Stackversion=1.04.358.30

Published CVSS scores

7.5NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.3Zero Day InitiativeCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-613Insufficient Session Expiration
T1499.004Application or System Exploitation

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.

Reported exploitation

Technologies

Your stack

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Your stack

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