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PatchSiren cyber security CVE debrief

CVE-2026-35089 Slican CVE debrief

A critical vulnerability in Slican telephone exchanges allows unauthenticated attackers to predictably generate administrative secure keys, enabling full system compromise. The flaw stems from deterministic key generation using exchange properties obtainable without authentication. Affected systems include IPx series, CCT-1668, MAC-6400, and CXS-0424 models. Patched versions are available for supported hardware, but end-of-life devices (versions 4.xx and below, discontinued 2011-2012) remain vulnerable and require hardware upgrades. The CVSS 4.0 score of 8.7 reflects high confidentiality impact with network-based, unauthenticated attack vectors. Organizations should prioritize patching supported devices and planning hardware replacements for discontinued models.

Vendor
Slican
Product
IPx
CVSS
HIGH 8.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-27
Original CVE updated
2026-05-27
Advisory published
2026-05-27
Advisory updated
2026-05-27

Who should care

Telecommunications infrastructure operators, PBX administrators, security teams managing voice networks, and organizations with legacy Slican telephone exchange deployments requiring hardware lifecycle planning.

Technical summary

The vulnerability exists in the secure key generation mechanism of Slican telephone exchanges. The key is derived using properties of the telephone exchange that can be obtained by an unauthenticated remote attacker. This deterministic generation allows attackers to compute the secure key and subsequently obtain administrative credentials. The flaw affects multiple product lines with varying patch availability. Supported devices receive firmware updates, while end-of-life hardware requires physical replacement to remediate.

Defensive priority

critical

Recommended defensive actions

  • Upgrade IPx series telephone exchanges to version 6.61.0040 or later
  • Upgrade CCT-1668 and MAC-6400 telephone exchanges to version 6.56.0430 or later
  • Upgrade CXS-0424 telephone exchanges to version 6.30.0510 or later
  • Contact Slican service department for hardware upgrade options on end-of-life CCT-1668 (CCT1CPU), MAC-6400, and CXS-0424 devices running version 4.xx or below
  • Implement network segmentation to restrict telephone exchange management interfaces from untrusted networks
  • Monitor for unauthorized administrative access attempts on affected telephone exchange systems
  • Inventory all Slican telephone exchange deployments to identify model versions and patch status

Evidence notes

Vulnerability disclosed via CERT.pl coordinated disclosure. CVSS 4.0 vector confirms network attack vector with no privileges required. Vendor acknowledges hardware dependency for patch deployment on EOL devices.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-35089 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-35089

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-35089 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-35089

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.