CVE-2021-25309
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 · uneditedThe telnet administrator service running on port 650 on Gigaset DX600A v41.00-175 devices does not implement any lockout or throttling functionality. This situation (together with the weak password policy that forces a 4-digit password) allows remote attackers to easily obtain administrative access via brute-force attacks.
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 · high confidenceThe Gigaset DX600A v41.00-175 telephone base station runs a telnet administrator service on port 650 that lacks any authentication lockout or rate-limiting mechanism. Combined with a weak default password policy that enforces only 4-digit PINs, attackers can trivially brute-force credentials to gain full administrative access remotely.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= v41.00-175CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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.
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Identify the device modelAccess the base station web interface or check the device label to confirm the model is Gigaset DX600AAffected if Device model is not Gigaset DX600A
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Check the firmware versionLog into the web interface and navigate to the settings or status page to view the firmware version, or use the telnet command to query the versionAffected if Firmware version is v41.00-175 exactly
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Verify telnet service accessibilityScan port 650 from a network-connected host using a tool such as nmap or telnet to confirm the telnet service is reachable: nmap -p 650 <device-ip>Affected if Port 650 is open and accepting connections
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Check PIN/password configurationLog into the telnet service on port 650 using valid credentials, then navigate to the user or security settings to inspect the configured PIN length and policyAffected if A 4-digit PIN is configured or no account lockout policy is visible
A user is affected if they have a Gigaset DX600A base station running firmware v41.00-175 with telnet port 650 exposed and using a 4-digit PIN without account lockout protection.
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 dataDisable the telnet service if possible and restrict management interface access to trusted networks or VPN; if telnet is required, implement network-level rate limiting or firewall rules to reduce brute-force exposure, and contact vendor for firmware that adds account lockout and stronger password requirements.
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-25309 — 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-2021-25309 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
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- 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