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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.

PUBLISHED Reserved 2026-04-14 | Published 2026-04-21 | Updated 2026-04-21 | Assigner GitHub_M




HIGH: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem types

CWE-704: Incorrect Type Conversion or Cast

Product status

< 4.10.0
affected

References

github.com/...coturn/security/advisories/GHSA-j662-9wcj-mf36 exploit

github.com/...coturn/security/advisories/GHSA-j662-9wcj-mf36

cve.org (CVE-2026-40613)

nvd.nist.gov (CVE-2026-40613)

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