How severe is CVE-2026-40613?

CVE-2026-40613 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-40613 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40613?

CVE-2026-40613 affects Coturn Project Coturn. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40613?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-40613 have an EU (EUVD) identifier?

Yes. CVE-2026-40613 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24228.

When was CVE-2026-40613 published?

CVE-2026-40613 was published on 2026-04-21 and last updated on 2026-06-17.

CVE-2026-40613

CVE-2026-40613 is a high-severity vulnerability in Coturn Project Coturn with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-704.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24228
Weakness: CWE-704
Affected product: Coturn Project Coturn
Published: 2026-04-21
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-40613?: CVE-2026-40613 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-40613 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40613?: CVE-2026-40613 affects Coturn Project Coturn. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40613?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-40613 have an EU (EUVD) identifier?: Yes. CVE-2026-40613 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24228.
When was CVE-2026-40613 published?: CVE-2026-40613 was published on 2026-04-21 and last updated on 2026-06-17.

References

https://github.com/coturn/coturn/security/advisories/GHSA-j662-9wcj-mf36

Affected products (1)

cpe:2.3:a:coturn_project:coturn:*:*:*:*:*:*:*:*

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