dbcve.org
Spa500ds FirmwareOperating system · Cisco

CVE-2023-20218

MEDIUM · 6.1 CVSS v3.1 Published 2023-08-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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
A vulnerability in web-based management interface of Cisco SPA500 Series Analog Telephone Adapters (ATAs) could allow an authenticated, remote attacker to to modify a web page in the context of a user's browser. This vulnerability is due to insufficient validation of user-supplied input by the web-based management interface of the affected software. An attacker could exploit this vulnerability by persuading a user to click a crafted link. A successful exploit could allow the attacker to alter the contents of a web page to redirect the user to potentially malicious websites, or the attacker could use this vulnerability to conduct further client-side attacks. Cisco will not release software updates that address this vulnerability. {{value}} ["%7b%7bvalue%7d%7d"])}]]

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 cross-site scripting (XSS) vulnerability in the web-based management interface of Cisco SPA500 Series ATAs. Due to insufficient validation of user-supplied input, an authenticated attacker can modify web page content in the context of a user's browser by tricking them into clicking a crafted link. This allows redirection to malicious websites or further client-side attacks.

MitigationSince Cisco will not release software updates, disable the web-based management interface if unused, or restrict access via network segmentation/VPN. Implement web application firewall rules to detect and block XSS payloads targeting the management 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
Spa500ds FirmwareOperating system
Affected:all versions
Spa500s FirmwareOperating system
Affected:all versions
Spa501g FirmwareOperating system
Affected:all versions
Spa502g FirmwareOperating system
Affected:all versions
Spa504g FirmwareOperating system
Affected:all versions
Spa508g FirmwareOperating system
Affected:all versions
Spa509g FirmwareOperating system
Affected:all versions
Spa512g FirmwareOperating system
Affected:all versions

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 checks

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

  1. Identify Cisco SPA500 Series ATA devices on your network
    Check your network inventory, DHCP leases, or physically inspect devices to find Cisco SPA500 series Analog Telephone Adapters. Look for model numbers: Spa500ds, Spa500s, Spa501g, Spa502g, Spa504g, Spa508g, Spa509g, or Spa512g.
    Affected if Any of these models are present on your network
  2. Verify the device web-based management interface is enabled
    Access the device admin page (typically http://[device IP]/admin or /admin/advanced) and navigate to the web server settings section. Check if the HTTP/HTTPS management interface is set to 'Enabled' or 'Yes'.
    Affected if The web-based management interface is enabled on the device
  3. Confirm network access to the management interface
    Attempt to reach the device web interface from your detection position: curl -I http://[device IP]/ or https://[device IP]/ . Check if HTTP/HTTPS ports (80/443 or custom) respond with a login page.
    Affected if The web management interface is reachable from your network segment
  4. Check if remote administration is allowed
    In the device web interface, look for 'Web Server' or 'Admin Access' settings. Check if 'Allow Web Access From' is set to 'WAN' or includes external networks, or if there are no IP restrictions limiting admin access.
    Affected if Remote (WAN) web management access is permitted or no IP access restrictions are configured
  5. Verify admin authentication is required for the affected interface
    Attempt to access the management pages without logging in. The vulnerability requires an authenticated attacker, so check if unauthenticated requests are rejected or redirected to a login page.
    Affected if You can access management functions without authentication (unauthenticated attacker scenario)

You are affected if you have any Cisco SPA500 Series ATA device (Spa500ds, Spa500s, Spa501g, Spa502g, Spa504g, Spa508g, Spa509g, Spa512g) with the web-based management interface enabled and accessible, regardless of firmware version since all versions are vulnerable.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Since Cisco will not release software updates, disable the web-based management interface if unused, or restrict access via network segmentation/VPN. Implement web application firewall rules to detect and block XSS payloads targeting the management interface.

Recommended fix High confidence
  1. This vulnerability has no available fix as Cisco has explicitly stated they will not release software updates for this vulnerability.
  2. Consider network segmentation to limit access to the web-based management interface.
  3. If possible, disable the web-based management interface and use alternative management methods.
  4. Monitor for suspicious links or unexpected browser behavior when accessing the device management interface.
  5. Implement additional authentication controls (e.g., VPN, firewall rules) to limit who can access the management interface.
  6. Consider replacing affected devices with newer models that receive security updates.

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

Fix this in Spa500ds Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
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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-2023-20218 in production — separate from our analysis above.

No notes yet

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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