Columbia Weather Systems MicroServer Command Shell in Externally Accessible Directory

published 2026-01-07 10 mo ago modified 2026-10-07 33 d ago also EUVD-2026-1166

cvss: 8.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

Columbia Weather Systems MicroServer MS_4.1_14142

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-26-006-01 updated 2026-01-06 cvss 8.0

Columbia Weather Systems MicroServer

Columbia Weather Systems MicroServer firmware <MS_4.1_14142
affected: vendor fix

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 10 mo ago (2026-01-07)

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.6	CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	3.1	8.0	CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA	4.0	8.6	CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	7.2	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Affected products

Columbia Weather Systems MicroServer

Classification

Weakness

CWE-553 Command Shell in Externally Accessible Directory

References

cisa.gov /news-events/ics-advisories/icsa-26-006-01
third-party-advisory, us-government-resource
github.com /cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-006-01.json
third-party-advisory

Sources

CVE List CVE-2025-66620
NVD CVE-2025-66620

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary