Vulnerability Details CVE-2026-40613
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 23.0%
CVSS Severity
CVSS v3 Score 7.5
References
Products affected by CVE-2026-40613
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cpe:2.3:a:coturn_project:coturn:4.4.5.3
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cpe:2.3:a:coturn_project:coturn:4.4.5.4
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cpe:2.3:a:coturn_project:coturn:4.5.0.1
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cpe:2.3:a:coturn_project:coturn:4.5.0.2
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cpe:2.3:a:coturn_project:coturn:4.5.0.3
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cpe:2.3:a:coturn_project:coturn:4.5.0.4
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cpe:2.3:a:coturn_project:coturn:4.5.0.5
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cpe:2.3:a:coturn_project:coturn:4.5.0.6
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cpe:2.3:a:coturn_project:coturn:4.5.0.7
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cpe:2.3:a:coturn_project:coturn:4.5.0.8
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cpe:2.3:a:coturn_project:coturn:4.5.0.9
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cpe:2.3:a:coturn_project:coturn:4.5.1.0
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cpe:2.3:a:coturn_project:coturn:4.5.1.1
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cpe:2.3:a:coturn_project:coturn:4.5.1.2
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cpe:2.3:a:coturn_project:coturn:4.5.1.3
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cpe:2.3:a:coturn_project:coturn:4.5.2
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cpe:2.3:a:coturn_project:coturn:4.6.0
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cpe:2.3:a:coturn_project:coturn:4.6.1
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cpe:2.3:a:coturn_project:coturn:4.6.2
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cpe:2.3:a:coturn_project:coturn:4.6.3
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cpe:2.3:a:coturn_project:coturn:4.7.0
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cpe:2.3:a:coturn_project:coturn:4.8.0
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cpe:2.3:a:coturn_project:coturn:4.9.0