What’s Vulnerable › Vulnerabilities

CVE-2021-33737

• Severity: high (CVSS 7.8 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-09-14 · updated 2026-06-17
• Weakness: CWE-119

Description

A vulnerability has been identified in SIMATIC CP 343-1 (incl. SIPLUS variants) (All versions), SIMATIC CP 343-1 Advanced (incl. SIPLUS variants) (All versions), SIMATIC CP 343-1 ERPC (All versions), SIMATIC CP 343-1 Lean (incl. SIPLUS variants) (All versions), SIMATIC CP 443-1 (All versions < V3.3), SIMATIC CP 443-1 (All versions < V3.3), SIMATIC CP 443-1 Advanced (All versions < V3.3), SIPLUS NET CP 443-1 (All versions < V3.3), SIPLUS NET CP 443-1 Advanced (All versions < V3.3). Sending a specially crafted packet to port 102/tcp of an affected device could cause a denial of service condition. A restart is needed to restore normal operations.

Affected products

• Siemens Simatic Cp 343-1 Advanced Firmware: all versions
• Siemens Simatic Cp 343-1 Erpc Firmware: all versions
• Siemens Simatic Cp 343-1 Firmware: all versions
• Siemens Simatic Cp 343-1 Lean Firmware: all versions
• Siemens Simatic Cp 443-1 Advanced Firmware: all versions
• Siemens Simatic Cp 443-1 Firmware: all versions

References

• https://cert-portal.siemens.com/productcert/pdf/ssa-549234.pdf
• https://cert-portal.siemens.com/productcert/pdf/ssa-549234.pdf

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