Vulnerability · Published Apr 21, 2026 · Assigned by GitHub_M
CVE-2026-40613Coturn: Misaligned Memory Access in coturn STUN Attribute Parser (Remote DoS on ARM64)
High 7.5
In plain English
A high-severity security flaw in coturn from coturn. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 66% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.10.0, the STUN/TURN attribute parsing functions in coturn perform unsafe pointer casts from uint8_t * to uint16_t * without alignment checks. When processing a crafted STUN message with odd-aligned attribute boundaries, this results in misaligned memory reads at ns_turn_msg.c. On ARM64 architectures (AArch64) with strict alignment enforcement, this causes a SIGBUS signal that immediately kills the turnserver process. An unauthenticated remote attacker can crash any ARM64 coturn deployment by sending a single crafted UDP packet. This vulnerability is fixed in 4.10.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | coturn | 4.10.0-r0 | ALPINE-CVE-2026-40613 |
| Alpine:v3.24 | coturn | 4.10.0-r0 | ALPINE-CVE-2026-40613 |
| Debian:12 | coturn | no fix listed | DEBIAN-CVE-2026-40613 |
| Debian:13 | coturn | no fix listed | DEBIAN-CVE-2026-40613 |
| Debian:14 | coturn | 4.12.0-1 | DEBIAN-CVE-2026-40613 |
| Ubuntu:22.04:LTS | coturn | no fix listed | UBUNTU-CVE-2026-40613 |
| Ubuntu:24.04:LTS | coturn | no fix listed | UBUNTU-CVE-2026-40613 |
| Ubuntu:25.10 | coturn | no fix listed | UBUNTU-CVE-2026-40613 |
| Ubuntu:26.04:LTS | coturn | no fix listed | UBUNTU-CVE-2026-40613 |
| Ubuntu:26.10 | coturn | no fix listed | UBUNTU-CVE-2026-40613 |
Affected products (as reported)
Weakness: CWE-704 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/coturn/coturn/security/advisories/GHSA-j662-9wcj-mf36 x_refsource_CONFIRM