Vulnerability · Published May 27, 2026 · Assigned by CERT-PL

CVE-2026-35089Use of Weak Credentials in Slican telephone exchanges

High 8.7

In plain English

A high-severity security flaw in CCT-1668 from Slican. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.6%top 51.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

In Slican telephone exchanges secure key is generated in a predictable manner using properties of the telephone exchange which can be obtained without authentication. An unauthenticated attacker can deduce the secure key and obtain admin credentials. This issue was fixed in versions below: - 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.

Affected products (as reported)

Vendor	Product	Versions
Slican	IPx	0 – before 6.61.0040
Slican	CCT-1668	0 – before 6.56.0430
Slican	MAC-6400	0 – before 6.56.0430
Slican	CXS-0424	0 – before 6.30.0510

Weakness: CWE-1391 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

References

https://cert.pl/posts/2026/05/CVE-2026-35087 third-party-advisory