How severe is CVE-2021-25676?

CVE-2021-25676 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-2021-25676 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-25676?

CVE-2021-25676 primarily affects Siemens Ruggedcom Rm1224 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-2021-25676?

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-2021-25676 published?

CVE-2021-25676 was published on 2021-03-15 and last updated on 2026-06-17.

CVE-2021-25676

CVE-2021-25676 is a high-severity vulnerability in Siemens Ruggedcom Rm1224 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-307.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-307
Affected product: Siemens Ruggedcom Rm1224 Firmware
Published: 2021-03-15
Last modified: 2026-06-17

Description

A vulnerability has been identified in RUGGEDCOM RM1224 (V6.3), SCALANCE M-800 (V6.3), SCALANCE S615 (V6.3), SCALANCE SC-600 (All Versions >= V2.1 and < V2.1.3). Multiple failed SSH authentication attempts could trigger a temporary Denial-of-Service under certain conditions. When triggered, the device will reboot automatically.

Frequently asked questions

What is CVE-2021-25676?: A vulnerability has been identified in RUGGEDCOM RM1224 (V6.3), SCALANCE M-800 (V6.3), SCALANCE S615 (V6.3), SCALANCE SC-600 (All Versions >= V2.1 and < V2.1.3). Multiple failed SSH authentication attempts could trigger a temporary Denial-of-Service under certain conditions. When triggered, the device will reboot automatically.
How severe is CVE-2021-25676?: CVE-2021-25676 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-2021-25676 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-25676?: CVE-2021-25676 primarily affects Siemens Ruggedcom Rm1224 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-2021-25676?: 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-2021-25676 published?: CVE-2021-25676 was published on 2021-03-15 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:siemens:ruggedcom_rm1224_firmware:6.3:*:*:*:*:*:*:*
cpe:2.3:o:siemens:scalance_m-800_firmware:6.3:*:*:*:*:*:*:*
cpe:2.3:o:siemens:scalance_s615_firmware:6.3:*:*:*:*:*:*:*
cpe:2.3:o:siemens:scalance_sc-600_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Siemens Ruggedcom Rm1224 Firmware

CVE-2017-14491 — Critical (CVSS 9.8): Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or…
CVE-2021-25667 — High (CVSS 8.8): A vulnerability has been identified in RUGGEDCOM RM1224 (All versions >= V4.3 and < V6.4), SCALANCE M-800 (All versions…
CVE-2022-31766 — High (CVSS 8.6): A vulnerability has been identified in RUGGEDCOM RM1224 LTE(4G) EU (6GK6108-4AM00-2BA2) (All versions < V7.1.2),…
CVE-2020-28400 — High (CVSS 7.5): Affected devices contain a vulnerability that allows an unauthenticated attacker to trigger a denial of service…
CVE-2019-13946 — High (CVSS 7.5): Profinet-IO (PNIO) stack versions prior V06.00 do not properly limit internal resource allocation when multiple…
CVE-2018-5391 — High (CVSS 7.5): The Linux kernel, versions 3.9+, is vulnerable to a denial of service attack with low rates of specially modified…

All CVEs affecting Siemens Ruggedcom Rm1224 Firmware →

Other CWE-307 (Improper Restriction of Excessive Authentication Attempts) vulnerabilities

CVE-2026-6853 — Critical (CVSS 9.8): Improper restriction of excessive authentication attempts vulnerability in Başbelen Group Food Cafe Businesses…
CVE-2026-8760 — Critical (CVSS 9.8): The Login with OTP plugin for WordPress is vulnerable to authentication bypass in all versions up to, and including,…
CVE-2020-37228 — Critical (CVSS 9.8): iDS6 DSSPro Digital Signage System 6.2 contains a CAPTCHA security bypass vulnerability that allows attackers to bypass…
CVE-2026-33879 — Critical (CVSS 9.8): Federated Learning and Interoperability Platform (FLIP) is an open-source platform for federated training and…
CVE-2026-33640 — Critical (CVSS 9.8): Outline is a service that allows for collaborative documentation. Outline implements an Email OTP login flow for users…
CVE-2026-31851 — Critical (CVSS 9.8): Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 does not implement rate limiting or account lockout…

Browse all CWE-307 (Improper Restriction of Excessive Authentication Attempts) vulnerabilities →