How severe is CVE-2018-4853?

CVE-2018-4853 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-4853 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-4853?

CVE-2018-4853 primarily affects Siemens Siclock Tc400 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-4853?

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

When was CVE-2018-4853 published?

CVE-2018-4853 was published on 2018-07-03 and last updated on 2026-06-17.

CVE-2018-4853

CVE-2018-4853 is a critical-severity vulnerability in Siemens Siclock Tc400 Firmware with a CVSS 3.x base score of 9.8. 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-306.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Siemens Siclock Tc400 Firmware
Published: 2018-07-03
Last modified: 2026-06-17

Description

A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with network access to port 69/udp could modify the firmware of the device.

Frequently asked questions

What is CVE-2018-4853?: A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with network access to port 69/udp could modify the firmware of the device.
How severe is CVE-2018-4853?: CVE-2018-4853 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-4853 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-4853?: CVE-2018-4853 primarily affects Siemens Siclock Tc400 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-4853?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-4853 published?: CVE-2018-4853 was published on 2018-07-03 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:siemens:siclock_tc400_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:siclock_tc100_firmware:-:*:*:*:*:*:*:*

More vulnerabilities in Siemens Siclock Tc400 Firmware

CVE-2018-4852 — Critical (CVSS 9.8): A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with…
CVE-2018-4854 — High (CVSS 8.8): A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with…
CVE-2018-4851 — High (CVSS 8.2): A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with…
CVE-2018-4855 — Medium (CVSS 6.5): A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). Unencrypted…
CVE-2018-4856 — Medium (CVSS 4.9): A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with…

All CVEs affecting Siemens Siclock Tc400 Firmware →

Other CWE-306 (Missing Authentication for Critical Function) vulnerabilities

CVE-2026-54309 — Critical (CVSS 10.0): n8n is an open source workflow automation platform. Prior to 2.25.7 and 2.26.2, when @n8n/mcp-browser is run in HTTP…
CVE-2026-50242 — Critical (CVSS 10.0): In JetBrains Hub before 2026.1.13757, 2025.3.148033, 2025.2.148048, 2025.1.148120, 2024.3.148430, 2024.2.148429…
CVE-2026-49257 — Critical (CVSS 10.0): mcp-pinot is a Python-based Model Context Protocol (MCP) server for interacting with Apache Pinot. In versions 3.0.1…
CVE-2026-46846 — Critical (CVSS 10.0): Vulnerability in the Oracle WebCenter Portal product of Oracle Fusion Middleware (component: Security Framework).…
CVE-2026-46803 — Critical (CVSS 10.0): Vulnerability in the Oracle WebCenter Portal product of Oracle Fusion Middleware (component: Security Framework).…
CVE-2026-46800 — Critical (CVSS 10.0): Vulnerability in the Oracle WebCenter Sites product of Oracle Fusion Middleware (component: WebCenter Sites).…

Browse all CWE-306 (Missing Authentication for Critical Function) vulnerabilities →