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Fencer Vulns
critical 9.9

CVE-2021-40358 json

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…

published 2021-11-09 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27536

cvss
9.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

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). Legitimate file operations on the web server of the affected systems do not properly neutralize special elements within the pathname. An attacker could then cause the pathname to resolve to a location outside of the restricted directory on the server and read, write or delete unexpected critical files.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-315-03 updated cvss 9.9

Siemens SIMATIC WinCC (Update E)

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

1.27% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • Siemens SIMATIC PCS 7 V8.2
  • Siemens SIMATIC PCS 7 V9.0
  • Siemens SIMATIC PCS 7 V9.1
  • Siemens SIMATIC WinCC V15 and earlier
  • Siemens SIMATIC WinCC V16
  • Siemens SIMATIC WinCC V17
  • Siemens SIMATIC WinCC V7.4
  • Siemens SIMATIC WinCC V7.5

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.