# CVE-2026-40613

## Summary

- **CVE ID:** CVE-2026-40613
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-704
- **Published:** Apr 21, 2026
- **Last Modified:** Apr 21, 2026

## 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 Products

- coturn — coturn (< 4.10.0)

## References

- [CNA](https://github.com/coturn/coturn/security/advisories/GHSA-j662-9wcj-mf36)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 1.12%
- **EPSS Percentile:** 64.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._