How severe is CVE-2019-18336?

CVE-2019-18336 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2019-18336 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-18336?

CVE-2019-18336 primarily affects Siemens Simatic S7-300 Cpu Firmware. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-18336?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-18336 published?

CVE-2019-18336 was published on 2020-03-10 and last updated on 2026-06-17.

CVE-2019-18336

CVE-2019-18336 is a high-severity vulnerability in Siemens Simatic S7-300 Cpu Firmware with a CVSS 3.x base score of 7.5. 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-400.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.8
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Siemens Simatic S7-300 Cpu Firmware
Published: 2020-03-10
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 < V3.X.17), SIMATIC TDC CP51M1 (All versions < V1.1.8), SIMATIC TDC CPU555 (All versions < V1.1.1), SINUMERIK 840D sl (All versions < V4.8.6), SINUMERIK 840D sl (All versions < V4.94). Specially crafted packets sent to port 102/tcp (Profinet) could cause the affected device to go into defect mode. A restart is required in order to recover the system. Successful exploitation requires an attacker to have network access to port 102/tcp, with no authentication. No user interation is required. At the time of advisory publication no public exploitation of this security vulnerability was known.

Frequently asked questions

What is CVE-2019-18336?: A vulnerability has been identified in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions < V3.X.17), SIMATIC TDC CP51M1 (All versions < V1.1.8), SIMATIC TDC CPU555 (All versions < V1.1.1), SINUMERIK 840D sl (All versions < V4.8.6), SINUMERIK 840D sl (All versions < V4.94). Specially crafted packets sent to port 102/tcp (Profinet) could cause the affected device to go into defect mode. A restart is required in order to recover the system. Successful exploitation requires an attacker to have network access to port 102/tcp, with no authentication. No user interation is required. At the time of advisory publication no public exploitation of this security vulnerability was known.
How severe is CVE-2019-18336?: CVE-2019-18336 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2019-18336 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-18336?: CVE-2019-18336 primarily affects Siemens Simatic S7-300 Cpu Firmware. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-18336?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-18336 published?: CVE-2019-18336 was published on 2020-03-10 and last updated on 2026-06-17.

References

https://cert-portal.siemens.com/productcert/pdf/ssa-508982.pdf

Affected products (12)

cpe:2.3:o:siemens:simatic_s7-300_cpu_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_312_ifm_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_313_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_314_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_314_ifm_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_315_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_315-2_dp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_316-2_dp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_s7-300_cpu_318-2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:a:siemens:sinumerik_840d_sl:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_tdc_cp51m1_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_tdc_cpu555_firmware:*:*:*:*:*:*:*:*

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CVE-2019-10923 — High (CVSS 7.5): An attacker with network access to an affected product may cause a denial of service condition by breaking the…
CVE-2016-9158 — High (CVSS 7.5): A vulnerability has been identified in SIMATIC S7-300 CPU family (All versions), SIMATIC S7-300 CPU family (incl.…
CVE-2015-2177 — High (CVSS 7.5): Siemens SIMATIC S7-300 CPU devices allow remote attackers to cause a denial of service (defect-mode transition) via…
CVE-2016-9159 — Medium (CVSS 5.9): A vulnerability has been identified in SIMATIC S7-300 CPU family (All versions), SIMATIC S7-300 CPU family (incl.…

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