CVE-2019-9555
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 · uneditedSagemcom F@st 5260 routers using firmware version 0.4.39, in WPA mode, default to using a PSK that is generated from a 2-part wordlist of known values and a nonce with insufficient entropy. The number of possible PSKs is about 1.78 billion, which is too small.
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 Sagemcom F@st 5260 router with firmware 0.4.39 generates default WiFi WPA PSKs using a weak algorithm combining a 2-part wordlist with a nonce, yielding only approximately 1.78 billion possible keys. This insufficient entropy makes the PSK vulnerable to offline brute-force attacks.
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= 0.4.39CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
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 router modelLocate the device label on the router or access the admin web interface (typically at 192.168.1.1) and check the device model nameAffected if The model is Sagemcom F@st 5260
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Check the firmware versionAccess the router admin web interface and navigate to Status or Management section to view the firmware versionAffected if The firmware version is exactly 0.4.39
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Locate the default WiFi PSKCheck the router device label for the default WiFi password printed on it, or access the wireless settings page in the admin interfaceAffected if The current WiFi PSK matches the factory default printed on the device label or is still in use
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Assess PSK complexityExamine the current WiFi PSK length and character composition - the weak algorithm generates PSKs from a limited 2-part wordlist combined with a nonceAffected if The PSK appears to follow a predictable pattern or was never changed from the default value
You are affected if you have a Sagemcom F@st 5260 router running firmware version 0.4.39 and are using the default factory-generated WiFi PSK that has not been changed to a strong, randomly-generated password.
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 dataUsers should immediately change the default WiFi PSK to a strong, randomly-generated password. Administrators should also check for and apply any firmware updates from Sagemcom that address the weak PSK generation algorithm.
- Consultation2.0 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 $4,480.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-9555 — 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-2019-9555 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
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