CVE-2021-40364: A vulnerability has been identified in SIMATIC PCS 7 V8.2 (All versions), SIMATIC PCS 7 V9.0 (All versions < V

Q: How do I fix CVE-2021-40364?

simatic pcs 7: upgrade to 9.1; simatic wincc: upgrade to newer than 7.4. Exact commands for each OS are on this page.

Q: Is CVE-2021-40364 being exploited?

CVE-2021-40364 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-40364 affect?

CVE-2021-40364 affects simatic pcs 7, simatic wincc. Severity is medium (CVSS 5.5). A vulnerability has been identified in SIMATIC PCS 7 V8.2 (All versions), SIMATIC PCS 7 V9.0 (All versions < V9.0 SP3 UC04), SIMATIC PCS 7 V9.1 (All versions < V9.1 SP1), SIMATIC WinCC V15 and earlier (All versions < V15 SP1 Update 7), SIMA

Q: How urgent is CVE-2021-40364?

Priority 23/100. No elevated risk signals yet.

Routine

MEDIUM 5.5UPGRADEUPGRADE

CVE-2021-40364 is a medium-severity flaw (CVSS 5.5) affecting simatic pcs 7, simatic wincc. 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 PCS 7 V8.2 (All versions), SIMATIC PCS 7 V9.0 (All versions < V9.0 SP3 UC04), SIMATIC PCS 7 V9.1 (All versions < V9.1 SP1), SIMATIC WinCC V15 and earlier (All versions < V15 SP1 Update 7), SIMATIC WinCC V16 (All versions < V16 Update 5), SIMATIC WinCC V17 (All versions < V17 Update 2), SIMATIC WinCC V7.4 (All versions < V7.4 SP1 Update 19), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 5). The a

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-532
Published	2021-11-09
Last modified	2026-06-17

Publisher (CNA): Siemens AG · Vendor: siemens

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-11-09 12:15 UTCPublished CVE record published
2026-06-17 04:06 UTCUpdated Record last modified

siemens simatic pcs 7 UPGRADE

Affected: <= 8.2 · >= 9.0 and < 9.1 · 9.1

Fixed in: 9.1

Safe to downgrade to: a release before 9.0

1. Check installed version

apt-cache policy simatic-pcs-7 || rpm -q simatic-pcs-7 || simatic-pcs-7 --version

2. UPGRADE to 9.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade simatic-pcs-7

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade simatic-pcs-7

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 9.0 (Debian / Ubuntu)

apt-cache madison simatic-pcs-7 sudo apt install simatic-pcs-7=<VERSION_BEFORE_9.0> sudo apt-mark hold simatic-pcs-7

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list simatic-pcs-7 sudo dnf downgrade simatic-pcs-7-<VERSION_BEFORE_9.0> sudo dnf versionlock add simatic-pcs-7

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

siemens simatic wincc UPGRADE

Affected: <= 7.4 · 7.5 · 7.5 sp1 · 7.5 sp1_update1 · 7.5 sp1_update2 · 7.5 sp2 · 7.5 sp2_update1 · 7.5 sp2_update2

Fixed in: newer than 7.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy simatic-wincc || rpm -q simatic-wincc || simatic-wincc --version

2. UPGRADE to newer than 7.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade simatic-wincc

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade simatic-wincc

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2021-40364?

simatic pcs 7: upgrade to 9.1; simatic wincc: upgrade to newer than 7.4. Exact commands for each OS are on this page.

Is CVE-2021-40364 being exploited?

CVE-2021-40364 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-2021-40364 affect?

CVE-2021-40364 affects simatic pcs 7, simatic wincc. Severity is medium (CVSS 5.5). A vulnerability has been identified in SIMATIC PCS 7 V8.2 (All versions), SIMATIC PCS 7 V9.0 (All versions < V9.0 SP3 UC04), SIMATIC PCS 7 V9.1 (All versions < V9.1 SP1), SIMATIC WinCC V15 and earlier (All versions < V15 SP1 Update 7), SIMA

How urgent is CVE-2021-40364?

Priority 23/100. No elevated risk signals yet.

Software pages

Siemens vulnerabilities

Related CVEs

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References

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