# CVE-2026-40613

> Vulnerability · severity: **HIGH** (CVSS 7.5).

## 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.

## Key facts

- **CVE ID:** CVE-2026-40613
- **Published:** 2026-04-21
- **CVSS severity:** HIGH
- **CVSS base score:** 7.5
- **CWE codes:** CWE-704

## Affected products

- `coturn_project:coturn`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40613

## Citation

> AI Analytics. CVE-2026-40613. Retrieved 2026-07-24 from https://api.ai-analytics.org/cve/CVE-2026-40613. Derived from NIST NVD. Licensed CC0.

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