CVE-2018-16561

CVE-2018-16561 is a high-severity vulnerability in Siemens Simatic S7-300 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-20.

Key facts

Description

A vulnerability has been identified in SIMATIC S7-300 CPUs (All versions < V3.X.16). The affected CPUs improperly validate S7 communication packets which could cause a Denial-of-Service condition of the CPU. The CPU will remain in DEFECT mode until manual restart. Successful exploitation requires an attacker to be able to send a specially crafted S7 communication packet to a communication interface of the CPU. This includes Ethernet, PROFIBUS, and Multi Point Interfaces (MPI). No user interaction or privileges are required to exploit the security vulnerability. The vulnerability could allow causing a Denial-of-Service condition of the core functionality of the CPU, compromising the availability of the system. At the time of advisory publication no public exploitation of this security vulnerability was known. Siemens confirms the security vulnerability and provides mitigations to resolve the security issue.

Frequently asked questions

What is CVE-2018-16561?
A vulnerability has been identified in SIMATIC S7-300 CPUs (All versions < V3.X.16). The affected CPUs improperly validate S7 communication packets which could cause a Denial-of-Service condition of the CPU. The CPU will remain in DEFECT mode until manual restart. Successful exploitation requires an attacker to be able to send a specially crafted S7 communication packet to a communication interface of the CPU. This includes Ethernet, PROFIBUS, and Multi Point Interfaces (MPI). No user interaction or privileges are required to exploit the security vulnerability. The vulnerability could allow causing a Denial-of-Service condition of the core functionality of the CPU, compromising the availability of the system. At the time of advisory publication no public exploitation of this security vulnerability was known. Siemens confirms the security vulnerability and provides mitigations to resolve the security issue.
How severe is CVE-2018-16561?
CVE-2018-16561 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-2018-16561 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-16561?
CVE-2018-16561 primarily affects Siemens Simatic S7-300 Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-16561?
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-2018-16561 published?
CVE-2018-16561 was published on 2019-04-17 and last updated on 2026-06-17.

References

Affected products (4)

More vulnerabilities in Siemens Simatic S7-300 Firmware

All CVEs affecting Siemens Simatic S7-300 Firmware →

Other CWE-20 (Improper Input Validation) vulnerabilities

Browse all CWE-20 (Improper Input Validation) vulnerabilities →