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CVE-2023-36521: A vulnerability has been identified in SIMATIC MV540 H (All versions < V3.3.4), SIMATIC MV540 S (All versions

47
This month
HIGH 8.6REMOTEUPGRADEUPGRADEUPGRADE

CVE-2023-36521 is a high-severity flaw (CVSS 8.6) affecting simatic mv540 h firmware, simatic mv540 s firmware, simatic mv550 h firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability has been identified in SIMATIC MV540 H (All versions < V3.3.4), SIMATIC MV540 S (All versions < V3.3.4), SIMATIC MV550 H (All versions < V3.3.4), SIMATIC MV550 S (All versions < V3.3.4), SIMATIC MV560 U (All versions < V3.3.4), SIMATIC MV560 X (All versions < V3.3.4). The result synchronization server of the affected products contains a vulnerability that may lead to a denial of service condition. An attacker may cause a denial

Why this priority

  • High severity
  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score8.6 (High)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance0.6% (top 51%)
CISA exploited listNo
WeaknessCWE-770
Published2023-07-11
Last modified2026-10-23
Publisher (CNA): Siemens AG · Vendor: siemens

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

siemens simatic mv540 h firmware UPGRADE
Affected: < 3.3.4
Fixed in: 3.3.4
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
siemens simatic mv540 s firmware UPGRADE
Affected: < 3.3.4
Fixed in: 3.3.4
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
siemens simatic mv550 h firmware UPGRADE
Affected: < 3.3.4
Fixed in: 3.3.4
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
siemens simatic mv550 s firmware UPGRADE
Affected: < 3.3.4
Fixed in: 3.3.4
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
siemens simatic mv560 u firmware UPGRADE
Affected: < 3.3.4
Fixed in: 3.3.4
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
siemens simatic mv560 x firmware UPGRADE
Affected: < 3.3.4
Fixed in: 3.3.4
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

Fedora 46 · python-trimesh · FIXED · 5.2.0-1.fc46 · FEDORA-2026-429b4bad4c · source
sudo dnf upgrade --advisory=FEDORA-2026-429b4bad4c
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-36521?

simatic mv540 h firmware: upgrade to 3.3.4; simatic mv540 s firmware: upgrade to 3.3.4; simatic mv550 h firmware: upgrade to 3.3.4. Exact commands for each OS are on this page.

Is CVE-2023-36521 being exploited?

CVE-2023-36521 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-36521 affect?

CVE-2023-36521 affects simatic mv540 h firmware, simatic mv540 s firmware, simatic mv550 h firmware. Severity is high (CVSS 8.6). A vulnerability has been identified in SIMATIC MV540 H (All versions < V3.3.4), SIMATIC MV540 S (All versions < V3.3.4), SIMATIC MV550 H (All versions < V3.3.4), SIMATIC MV550 S (All versions < V3.3.4), SIMATIC MV560 U (All versions < V3.3.

How urgent is CVE-2023-36521?

Priority 47/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

References

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