CRITICAL · CVSS 9.8 CISA Known Exploited Vulnerability

CVE-2026-72529

TrueConf Server Missing Authentication for Critical Function Vulnerability

TrueConf Server

A remote unauthorized attacker with network access via port 4307/TCP to the TrueConf server versions 5.3.X to 5.3.9, 5.4.X to 5.4.9, 5.5.X to 5.5.5, and earlier could execute an arbitrary script by calling an undocumented function.

CVSS
9.8
CRITICAL
EPSS
1.6%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
19 Aug 2026
CWE-306

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 20 August 2026. US federal agencies were required to remediate it by 23 August 2026.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 1.6%, which is higher than 74% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Frequently asked questions

Is CVE-2026-72529 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2026-72529.

What does CVE-2026-72529 affect?

CVE-2026-72529 affects TrueConf Server. A remote unauthorized attacker with network access via port 4307/TCP to the TrueConf server versions 5.3.X to 5.3.9, 5.4.X to 5.4.9, 5.5.X to 5.5.5, and earlier could execute an arbitrary script by calling an undocumented function.

How severe is CVE-2026-72529?

CVE-2026-72529 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 1.6%, higher than 74% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 23 August 2026.

How should organisations respond to CVE-2026-72529?

Apply the vendor patch for TrueConf Server as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.