CVE-2025-61939: An unused function in MicroServer can start a reverse SSH connection to a vendor registered domain, without mu

Q: How do I fix CVE-2025-61939?

weather microserver firmware: upgrade to MS_4.1_14142. Exact commands for each OS are on this page.

Q: Is CVE-2025-61939 being exploited?

CVE-2025-61939 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-61939 affect?

CVE-2025-61939 affects weather microserver firmware. Severity is high (CVSS 8.8). An unused function in MicroServer can start a reverse SSH connection to a vendor registered domain, without mutual authentication. An attacker on the local network with admin access to the web server, and the ability to manipulate DNS respo

Routine

HIGH 8.8UPGRADE

CVE-2025-61939 is a high-severity flaw (CVSS 8.8) affecting weather microserver firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An unused function in MicroServer can start a reverse SSH connection to a vendor registered domain, without mutual authentication. An attacker on the local network with admin access to the web server, and the ability to manipulate DNS responses, can redirect the SSH connection to an attacker controlled device.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Weakness	CWE-923
Published	2026-01-07
Last modified	2026-10-07

Publisher (CNA): ICS-CERT · Vendor: columbiaweather

Last updated 2026-10-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-01-07 21:15 UTCPublished CVE record published
2026-10-07 09:10 UTCUpdated Record last modified

columbiaweather weather microserver firmware UPGRADE

Affected: < MS_4.1_14142

Fixed in: MS_4.1_14142

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-61939?

weather microserver firmware: upgrade to MS_4.1_14142. Exact commands for each OS are on this page.

Is CVE-2025-61939 being exploited?

CVE-2025-61939 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-61939 affect?

CVE-2025-61939 affects weather microserver firmware. Severity is high (CVSS 8.8). An unused function in MicroServer can start a reverse SSH connection to a vendor registered domain, without mutual authentication. An attacker on the local network with admin access to the web server, and the ability to manipulate DNS respo

How urgent is CVE-2025-61939?

Priority 36/100. High severity

Related CVEs

CVE-2025-66620 HIGH 8.0 UPGRADE An unused webshell in MicroServer allows unlimited login attempts, with sudo rights on certain files and direc

References

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