Quantum Secular Labs / Blog / Advisories
CVE-2026-72529: TrueConf Server Missing Authentication for Critical Function Vulnerability
CVE-2026-72529 is rated critical with a CVSS v3.1 base score of 9.8 and affects TrueConf Server. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-08-20, which means exploitation in the wild has been observed.
Vulnerability description
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.
Severity breakdown
CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
- Attack complexity: Low. No special conditions; the attack can be repeated reliably.
- Privileges required: None. No account or prior access is needed.
- User interaction: None. No action from any user is needed.
- Scope: Unchanged. Impact stays within the vulnerable component.
- Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
- Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
- Availability impact: High. Total loss of availability; the component can be shut down.
Underlying weakness
CWE-306: Missing Authentication for Critical Functionality
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
Affected products
- Trueconf Server: before 5.3.9.10013; before 5.3.9.10015; from 5.4.0.12689 before 5.4.9.10072; from 5.4.0.12700 before 5.4.9.10019; from 5.5.0.13826 before 5.5.5.10010; from 5.5.0.13828 before 5.5.5.10009