What’s Vulnerable › Vulnerabilities

CVE-2026-62959: Coturn: Pre-authentication heap memory disclosure in ACME redirect (`try_acme_redirect`)

• Severity: high (CVSS 8.2 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-31 · updated 2026-09-09
• Weakness: CWE-125

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.

Affected products

• coturn: from 4.5.2, < 4.15.0

References

• https://github.com/coturn/coturn/commit/960835886692fa04cf63ddd970c3f330740c87f4
• https://github.com/coturn/coturn/pull/1965
• https://github.com/coturn/coturn/releases/tag/4.15.0
• https://github.com/coturn/coturn/security/advisories/GHSA-m23x-5qf5-988g
• https://github.com/coturn/coturn/security/advisories/GHSA-m23x-5qf5-988g

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