How severe is CVE-2020-15791?

CVE-2020-15791 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2020-15791 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-15791?

CVE-2020-15791 primarily affects Siemens Simatic S7-300 Cpu 312 Firmware. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-15791?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-15791 published?

CVE-2020-15791 was published on 2020-09-09 and last updated on 2026-06-17.

CVE-2020-15791

CVE-2020-15791 is a medium-severity vulnerability in Siemens Simatic S7-300 Cpu 312 Firmware with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-522.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 3.3
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-522
Affected product: Siemens Simatic S7-300 Cpu 312 Firmware
Published: 2020-09-09
Last modified: 2026-06-17

Description

A vulnerability has been identified in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions), SIMATIC S7-400 CPU family (incl. SIPLUS variants) (All versions), SIMATIC WinAC RTX (F) 2010 (All versions), SINUMERIK 840D sl (All versions). The authentication protocol between a client and a PLC via port 102/tcp (ISO-TSAP) insufficiently protects the transmitted password. This could allow an attacker that is able to intercept the network traffic to obtain valid PLC credentials.

Frequently asked questions

What is CVE-2020-15791?: A vulnerability has been identified in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions), SIMATIC S7-400 CPU family (incl. SIPLUS variants) (All versions), SIMATIC WinAC RTX (F) 2010 (All versions), SINUMERIK 840D sl (All versions). The authentication protocol between a client and a PLC via port 102/tcp (ISO-TSAP) insufficiently protects the transmitted password. This could allow an attacker that is able to intercept the network traffic to obtain valid PLC credentials.
How severe is CVE-2020-15791?: CVE-2020-15791 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2020-15791 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-15791?: CVE-2020-15791 primarily affects Siemens Simatic S7-300 Cpu 312 Firmware. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-15791?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-15791 published?: CVE-2020-15791 was published on 2020-09-09 and last updated on 2026-06-17.

References

https://cert-portal.siemens.com/productcert/pdf/ssa-381684.pdf

Affected products (14)

cpe:2.3:o:siemens:simatic_s7-300_cpu_312_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_314_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_315-2_dp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_315-2_pn_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_317-2_pn_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_317-2_dp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_315f-2_dp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_315f-2_pn_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_317f-2_pn_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_317f-2_dp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-400_cpu_412_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-400_cpu_414_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-400_cpu_416_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-400_cpu_417_firmware:*:*:*:*:*:*:*:*

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