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Vulnerability · Published Jul 31, 2026 · Assigned by GitHub_M

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

High 8.2

In plain English

A high-severity out-of-bounds read in coturn from coturn. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.2High
Exploit odds (30 days)0.5%top 55.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12coturnno fix listedDEBIAN-CVE-2026-62959
Debian:13coturnno fix listedDEBIAN-CVE-2026-62959
Debian:14coturn4.15.0-1DEBIAN-CVE-2026-62959
Ubuntu:22.04:LTScoturnno fix listedUBUNTU-CVE-2026-62959
Ubuntu:24.04:LTScoturnno fix listedUBUNTU-CVE-2026-62959
Ubuntu:26.04:LTScoturnno fix listedUBUNTU-CVE-2026-62959
Ubuntu:26.10coturnno fix listedUBUNTU-CVE-2026-62959

Affected products (as reported)

VendorProductVersions
coturn coturn >= 4.5.2, < 4.15.0

Weakness: CWE-125, CWE-195 · 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

References