CVE-2025-43980
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn issue was discovered on FIRSTNUM JC21A-04 devices through 2.01ME/FN. They enable the SSH service by default with the credentials of root/admin. The GUI doesn't offer a way to disable the account.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThe FIRSTNUM JC21A-04 devices through version 2.01ME/FN have SSH service enabled by default with hardcoded credentials (root/admin). The GUI offers no way to disable this account or change the credentials, creating an authentication bypass vector.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify device modelAccess the device's web GUI or console and check the model number displayed, or query the device using SNMP, telnet, or SSH banner grabbing to confirm it is a FIRSTNUM JC21A-04 deviceAffected if The device is a FIRSTNUM JC21A-04 unit
-
Check SSH service statusAttempt to connect to the device on TCP port 22 (SSH). If the connection succeeds, SSH is enabled. Alternatively, access the device CLI and run commands like 'show services' or 'show ssh status' if availableAffected if SSH service is listening and accepts connections on port 22
-
Verify hardcoded credentialsAttempt SSH authentication using the hardcoded credentials root/admin (username: root, password: admin). If login succeeds, the vulnerability is presentAffected if SSH login succeeds with root/admin credentials
-
Check firmware versionAccess the device web GUI system information page, CLI 'show version' command, or check the boot logs to determine the installed firmware version numberAffected if Firmware version is 2.01ME/FN or earlier (any version through 2.01ME/FN)
-
Check GUI for SSH management optionsNavigate through the device web GUI settings to locate SSH service configuration. Look for options to disable SSH, change SSH passwords, or remove the root account. Attempt to change or disable the root/admin accountAffected if No option exists in the GUI to disable SSH or change the hardcoded credentials, and the root/admin account remains active
A user is affected if they have a FIRSTNUM JC21A-04 device running firmware version 2.01ME/FN or earlier with SSH enabled, and the root/admin hardcoded credentials cannot be changed or disabled through the GUI.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataSince no vendor patch is referenced, organizations should restrict SSH access at network boundaries, implement compensating controls such as firewall rules or network segmentation, and contact the vendor for a firmware update addressing the hardcoded credentials.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-43980 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-43980 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data