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F\@st 3686 FirmwareOperating system · Sagemcom

CVE-2024-1623

HIGH · 7.8 CVSS v3.1 Published 2024-03-14
Fix available
A fix is available. Upgrade to 3.709.2 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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 · unedited
Insufficient session timeout vulnerability in the FAST3686 V2 Vodafone router from Sagemcom. This vulnerability could allow a local attacker to access the administration panel without requiring login credentials. This vulnerability is possible because the 'Login.asp and logout.asp' files do not handle session details correctly.

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 confidence

This is a session management vulnerability in Sagemcom FAST3686 V2 Vodafone routers where the Login.asp and logout.asp files fail to properly invalidate or timeout user sessions. A local attacker can access the administrative panel without credentials by exploiting an active session that should have been terminated.

MitigationApply the vendor-supplied firmware update to patch the session handling logic in Login.asp and logout.asp. If no update is available, restrict physical and local network access to the router's administrative interface.

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
F\@st 3686 FirmwareOperating system
Affected:< 3.709.2

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the router model
    Access the router's web admin interface or check the device label for the model number - look for Sagemcom F@st 3686 or FAST3686
    Affected if The device is not a Sagemcom F@st 3686 router - this vulnerability only affects that specific model
  2. Check the firmware version
    In the router's web admin interface, navigate to the Status or Administration page to view the firmware version. Alternatively, check the vendor firmware file or the device's system information page.
    Affected if The installed firmware version is below 3.709.2 (for example, 3.709.1, 3.708.x, or earlier)
  3. Confirm web admin interface accessibility
    Attempt to access the router's login page at http://<router-ip>/Login.asp or check if port 80/443 is open on the router's local IP address
    Affected if The administrative web interface is exposed and accessible on the local network
  4. Verify session handling configuration
    In the router's web admin interface, check the session management or timeout settings under Security or Administration menus. Look for session timeout duration values.
    Affected if There is no session timeout configured, or the timeout value is set to an excessive duration (such as 0 or never), indicating sessions may not be properly invalidated

A user is affected if they have a Sagemcom F@st 3686 router running firmware version 3.709.1 or earlier with an accessible web admin interface.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to 3.709.2 or later
Fixed in 3.709.2
Interim mitigation

Apply the vendor-supplied firmware update to patch the session handling logic in Login.asp and logout.asp. If no update is available, restrict physical and local network access to the router's administrative interface.

Recommended fix High confidence

F@st 3686 Firmware version 3.709.2 or later

  1. 1. Download the firmware version 3.709.2 or later from the official Sagemcom support site or Vodafone firmware repository
  2. 2. Access the router administration panel by entering the router's IP address in a web browser (typically 192.168.0.1 or 192.168.1.1)
  3. 3. Log in with administrator credentials
  4. 4. Navigate to the 'Administration' or 'System' section of the router settings
  5. 5. Look for 'Firmware Upgrade' or 'Software Update' option
  6. 6. Select the option to upload the new firmware file downloaded in step 1
  7. 7. Wait for the firmware upload and installation to complete (do not power off the router during this process)
  8. 8. After the router restarts, verify the firmware version in the router settings to confirm the upgrade was successful
Caveat Firmware upgrade may reset router configuration to defaults; back up current settings before upgrading if possible

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in F\@st 3686 Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-1623 in production — separate from our analysis above.

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What this is

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.

What belongs here
  • 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