How severe is CVE-2018-4851?

CVE-2018-4851 has a CVSS 3.x base score of 8.2, 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 low, and availability high.

Is CVE-2018-4851 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-4851?

CVE-2018-4851 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-2018-4851?

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-2018-4851 published?

CVE-2018-4851 was published on 2018-07-03 and last updated on 2026-06-17.

CVE-2018-4851

CVE-2018-4851 is a high-severity vulnerability in Siemens Siclock Tc400 Firmware with a CVSS 3.x base score of 8.2. 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

Severity: High (CVSS 3.x base score 8.2)
CVSS v2: 8.5
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
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 the device could cause a Denial-of-Service condition by sending certain packets to the device, causing potential reboots of the device. The core functionality of the device could be impacted. The time serving functionality recovers when time synchronization with GPS devices or other NTP servers are completed.

Frequently asked questions

What is CVE-2018-4851?: A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with network access to the device could cause a Denial-of-Service condition by sending certain packets to the device, causing potential reboots of the device. The core functionality of the device could be impacted. The time serving functionality recovers when time synchronization with GPS devices or other NTP servers are completed.
How severe is CVE-2018-4851?: CVE-2018-4851 has a CVSS 3.x base score of 8.2, 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 low, and availability high.
Is CVE-2018-4851 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-4851?: CVE-2018-4851 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-2018-4851?: 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-2018-4851 published?: CVE-2018-4851 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-2018-4853 — Critical (CVSS 9.8): A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with…
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-2018-4855 — 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…

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