CVE-2021-31893

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-07-13 · updated 2026-06-17
Weakness: CWE-120

Description

A vulnerability has been identified in SIMATIC PCS 7 V8.2 and earlier (All versions), SIMATIC PCS 7 V9.0 (All versions < V9.0 SP3), SIMATIC PDM (All versions < V9.2), SIMATIC STEP 7 V5.X (All versions < V5.6 SP2 HF3), SINAMICS STARTER (containing STEP 7 OEM version) (All versions < V5.4 HF2). The affected software contains a buffer overflow vulnerability while handling certain files that could allow a local attacker to trigger a denial-of-service condition or potentially lead to remote code execution.

Affected products

Siemens Simatic Pcs Firmware: through 8.2; 9.0, 9.0-sp1, 9.0-sp2
Siemens Simatic Pdm Firmware: before 9.2 — fixed in 9.2
Siemens Simatic Step 7 Firmware: through 5.6
Siemens Sinamics Starter Firmware: before 5.4; 5.4, 5.4-hotfix_1, 5.4-hotfix_2 — fixed in 5.4

How to fix

Upgrade to a fixed version: Siemens Simatic Pdm Firmware 9.2; Siemens Sinamics Starter Firmware 5.4. Check the vendor advisory for mitigations.

References

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