CVE-2026-43915: Coturn: Stored Cross-Site Scripting (XSS) in web-admin interface via TURN username

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-18 · updated 2026-06-26
Weakness: CWE-79

Description

Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.11.0 contain a stored cross-site scripting (XSS) vulnerability in the web-admin HTTPS interface. An attacker who can create a TURN allocation with a crafted USERNAME value can inject HTML/JavaScript that executes when an authenticated web-admin user views the TURN session list. In configurations using anonymous TURN access (--no-auth), this may be exploitable without TURN credentials. In authenticated deployments, exploitation requires valid TURN credentials or control over a provisioned username. This issue has been fixed in version 4.11.0.

Affected products

coturn: before 4.11.0 — fixed in 4.11.0

How to fix

Upgrade to a fixed version: coturn 4.11.0. Check the vendor advisory for mitigations.

References

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