How severe is CVE-2025-66620?

CVE-2025-66620 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-66620 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66620?

CVE-2025-66620 affects Columbiaweather Weather Microserver Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-66620?

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.

Does CVE-2025-66620 have an EU (EUVD) identifier?

Yes. CVE-2025-66620 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1166.

When was CVE-2025-66620 published?

CVE-2025-66620 was published on 2026-01-07 and last updated on 2026-06-17.

CVE-2025-66620

CVE-2025-66620 is a high-severity vulnerability in Columbiaweather Weather Microserver Firmware with a CVSS 3.x base score of 8.0. 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-553.

Key facts

Severity: High (CVSS 3.x base score 8.0)
CVSS v4: 8.6
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-1166
Weakness: CWE-553
Affected product: Columbiaweather Weather Microserver Firmware
Published: 2026-01-07
Last modified: 2026-06-17

Description

An unused webshell in MicroServer allows unlimited login attempts, with sudo rights on certain files and directories. An attacker with admin access to MicroServer can gain limited shell access, enabling persistence through reverse shells, and the ability to modify or remove data stored in the file system.

Frequently asked questions

What is CVE-2025-66620?: An unused webshell in MicroServer allows unlimited login attempts, with sudo rights on certain files and directories. An attacker with admin access to MicroServer can gain limited shell access, enabling persistence through reverse shells, and the ability to modify or remove data stored in the file system.
How severe is CVE-2025-66620?: CVE-2025-66620 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-66620 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66620?: CVE-2025-66620 affects Columbiaweather Weather Microserver Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-66620?: 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.
Does CVE-2025-66620 have an EU (EUVD) identifier?: Yes. CVE-2025-66620 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1166.
When was CVE-2025-66620 published?: CVE-2025-66620 was published on 2026-01-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:columbiaweather:weather_microserver_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Columbiaweather Weather Microserver Firmware

CVE-2025-61939 — High (CVSS 8.8): An unused function in MicroServer can start a reverse SSH connection to a vendor registered domain, without mutual…
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CVE-2018-18879 — High (CVSS 8.8): In firmware version MS_2.6.9900 of Columbia Weather MicroServer, an authenticated web user can pipe commands directly…
CVE-2018-18878 — High (CVSS 7.5): In firmware version MS_2.6.9900 of Columbia Weather MicroServer, the BACnet daemon does not properly validate input,…
CVE-2018-18875 — Medium (CVSS 5.4): In firmware version MS_2.6.9900 of Columbia Weather MicroServer, a stored Cross-site scripting (XSS) vulnerability…
CVE-2018-18880 — Medium (CVSS 5.4): In firmware version MS_2.6.9900 of Columbia Weather MicroServer, a networkdiags.php reflected Cross-site scripting…

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