CVE-2026-62959

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

HIGH
8.2
CVSS Score
Published: July 31, 2026 at 07:57 PM UTC
Updated: September 9, 2026 at 09:07 PM UTC
1 product affected across 1 vendorCoturn

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Severity
HIGH8.2
Exploit prediction
EPSS 0.5%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.15.0
Affected range stops below 4.15.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-125CWE-195

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