CVE-2026-40613
HIGHDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 64% of all known CVEs.
References
Related Vulnerabilities
Other CWE-704 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-41646 | Critical | 9.8 | 47% | - | Fix |
| CVE-2017-5115 | High | 8.8 | 26% | - | Fix |
| CVE-2018-3843 | High | 8.8 | 24% | - | - |
| CVE-2018-12453 | High | 7.5 | 24% | - | Fix |
| CVE-2017-3106 | High | 8.8 | 22% | - | - |
| CVE-2018-5007 | High | 8.8 | 18% | - | - |
Common questions
How do I fix CVE-2026-40613?
Upgrade coturn on debian unstable to 4.12.0-1 or later.
Is CVE-2026-40613 being actively exploited?
Not that we know of. CVE-2026-40613 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.1% is the estimated probability that it will be exploited in the next 30 days. That is higher than 64% of all scored CVEs.
How severe is CVE-2026-40613?
CVE-2026-40613 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-40613 affect?
Published advisories record a fix for coturn (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-24.