Coturn is a free open source implementation of TURN and STUN Server. From 4.5.2 through 4.14.0, when Coturn is started with --acme-redirect <URL> and exposes a plaintext-TCP listener, an unauthenticated remote client can send a single ordinary HTTP GET request and receive a 301 response whose Location header contains up to ~870 bytes of adjacent process heap memory. The leaked region is a recycled network receive buffer that is reused without being zeroed, so on a busy server it can contain data from other clients' requests (TURN credentials, OAuth tokens, relayed payloads). Root cause is a signed→unsigned conversion. This issue is fixed in version 4.15.0.
https://github.com/coturn/coturn/security/advisories/GHSA-m23x-5qf5-988g
https://github.com/coturn/coturn/releases/tag/4.15.0
https://github.com/coturn/coturn/pull/1965
https://github.com/coturn/coturn/commit/960835886692fa04cf63ddd970c3f330740c87f4
Published: 2026-07-31
Updated: 2026-08-01
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N
Severity: Medium
Base Score: 9.3
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H
Severity: Critical
Base Score: 8.2
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Severity: High