CWE-288Weakness · CWE-288

CVE-2026-35087

CRITICAL · 9.3 CVSS v4.0 Published 2026-05-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
Slican telephone exchanges allow administrative protocol authentication bypass. An attacker can bypass the need to enter login credentials by executing the appropriate command. This issue was fixed in versions below: - NCP: version 1.24.0250 - IPx series: version 6.61.0040 - CCT-1668: version 6.56.0430 - MAC-6400: version 6.56.0430 - CXS-0424: version 6.30.0510 The issue STILL EXISTS in End-Of-Life telephone exchanges in versions 4.xx and below: - CCT-1668 (CCT1CPU) - MAC-6400 - CXS-0424 These products were discontinued in 2011 and 2012 and and will not receive updates. These products require a hardware update in order to receive a software update. The vendor recommends that users of these devices contact the their service department directly to determine the options for upgrading.

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

Slican telephone exchanges contain an authentication bypass vulnerability in their administrative protocol. Attackers can execute administrative commands without providing valid login credentials by sending specially crafted commands to the device.

MitigationUpdate affected non-EOL devices to the specified fixed versions. For EOL products (CCT-1668, MAC-6400, CXS-0424), contact Slican service department for hardware upgrade options; implement network segmentation to limit exposure until replacement.

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
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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 Slican telephone exchange devices on the network
    Scan the network for devices with Slican product signatures, or review hardware inventory for Slican CCT-1668, MAC-6400, CXS-0424, or other Slican telephone exchange models
    Affected if Any Slican telephone exchange device is present in the environment
  2. Confirm administrative protocol is network-accessible
    Check firewall rules and network exposure for ports used by the Slican administrative protocol (typically ports 80/443 or vendor-specific management ports if known; otherwise verify the management interface is reachable from network segments other than dedicated admin VLANs)
    Affected if The administrative interface is reachable from network segments beyond a dedicated administrative VLAN
  3. Determine the device model and firmware version
    Access the device administrative interface or check device documentation/labels for the exact model number (CCT-1668, MAC-6400, CXS-0424, or other Slican models) and current firmware version
    Affected if The device is a CCT-1668, MAC-6400, or CXS-0424 model, or any Slican exchange running a version prior to vendor fixes
  4. Verify if network segmentation is applied
    Review network architecture to confirm the device administrative port is isolated behind a firewall or on a dedicated management VLAN with restricted access
    Affected if The administrative interface has direct exposure to untrusted networks without firewall filtering or VLAN isolation

The environment is affected if any Slican telephone exchange device is present and its administrative protocol is network-accessible without proper segmentation.

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

Update affected non-EOL devices to the specified fixed versions. For EOL products (CCT-1668, MAC-6400, CXS-0424), contact Slican service department for hardware upgrade options; implement network segmentation to limit exposure until replacement.

Recommended fix Moderate confidence

Upgrade to NCP v1.24.0250 / IPx v6.61.0040 / CCT-1668 v6.56.0430 / MAC-6400 v6.56.0430 / CXS-0424 v6.30.0510 (or newer)

  1. 1. Identify the specific Slican telephone exchange model (NCP, IPx series, CCT-1668, MAC-6400, or CXS-0424) in use
  2. 2. Check the current firmware version of the device
  3. 3. For non-EOL products (NCP, IPx series, CCT-1668, MAC-6400, CXS-0424 with versions above 4.xx): upgrade firmware to the fixed version: NCP to 1.24.0250, IPx to 6.61.0040, CCT-1668 to 6.56.0430, MAC-6400 to 6.56.0430, or CXS-0424 to 6.30.0510
  4. 4. For EOL products (CCT-1668, MAC-6400, CXS-0424 on versions 4.xx and below): contact Slican service department to arrange hardware upgrade required for software updates
Caveat Standard firmware upgrade risks apply - backup configuration before updating; EOL products require hardware replacement

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

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
36.0 hours of engineering $6,400
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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-2026-35087 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
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  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data