CVE-2026-40613Public exploitNetwork attack vector

Remote service crash via misaligned attribute dereference

Published Apr 21, 2026 · Updated Apr 21, 2026

Incorrect type conversion in coturn before 4.10.0 allows remote attackers to crash ARM64 turnserver processes via crafted STUN packets. stun_attr_get_next_str advances by an unpadded odd attribute length, after which stun_attr_get_len casts the resulting odd-aligned byte pointer to uint16_t * and dereferences it. A single unauthenticated UDP packet triggers SIGBUS on AArch64 systems with strict alignment, terminating the service without affecting confidentiality or integrity.

CVSS severity7.5
High
EPSS probability1.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect type conversion in coturn before 4.10.0 allows remote attackers to crash ARM64 turnserver processes via crafted STUN packets. stun_attr_get_next_str advances by an unpadded odd attribute length, after which stun_attr_get_len casts the resulting odd-aligned byte pointer to uint16_t * and dereferences it. A single unauthenticated UDP packet triggers SIGBUS on AArch64 systems with strict alignment, terminating the service without affecting confidentiality or integrity.

The record

CVE
CVE-2026-40613
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
coturn
Product
coturn
Classifications
CWE-704, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.10.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

coturn · coturnversion=< 4.10.0

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-704Incorrect Type Conversion or Cast
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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