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

CVE-2026-35087Authentication Bypass in Slican telephone exchanges

Critical 9.3

In plain English

A critical-severity authentication bypass 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 0.7% (higher than 52% of all known vulnerabilities).

Severity (CVSS 4.0)9.3Critical

Exploit odds (30 days)0.7%top 48.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

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
Slican	NCP	0 – before 1.24.0250

Weakness: CWE-288 · Vector: 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

References

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