CVE-2026-62959: coturn Out-of-bounds Read

Vulnerability summary

CVE-2026-62959 is a high (CVSS 8.2) Out-of-bounds Read vulnerability in coturn. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 43.5% of scored vulnerabilities.

Timeline

1. 31-07-2026
   PublishedVulnerability first disclosed.
2. 31-07-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.
• CWE-195Signed to Unsigned Conversion ErrorThe product uses a signed primitive and performs a cast to an unsigned primitive, which can produce an unexpected value if the value of the signed primitive can not be represented using an unsigned primitive.