The coturn server can end in a state where it does not accept more requests with "even-port" enabled.
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-400.
Summary
Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.17.0, turnports_allocate_even() in src/apps/relay/turn_ports.c marks the unused odd sibling port as TPS_TAKEN_ODD for an EVEN-PORT Allocate request with reservation bit R=0 even though no RTCP socket will release it, allowing an authenticated client to permanently exhaust the relay port pool and cause subsequent allocations to fail with STUN error 508. This issue is fixed in version 4.17.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA coturn (coturn) Fixed in 4.17.0
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-73215
References
More coturn vulnerabilities
- TI-2026-32037 Coturn: Stack buffer overflow in decode_oauth_token_gcm() CVSS 3.1CRITICAL 9.8
- TI-2026-44985 Coturn: Pre-authentication heap memory disclosure in ACME redirect (`try_acme_redirect`) CVSS 4.0HIGH 8.2
- TI-2026-29348 Coturn: Misaligned Memory Access in coturn STUN Attribute Parser (Remote DoS on ARM64) CVSS 3.1HIGH 7.5
- TI-2026-22006 Coturn: IPv4-mapped IPv6 (::ffff:0:0/96) bypasses denied-peer-ip ACL CVSS 3.1HIGH 7.2
- TI-2026-38529 Coturn: SQL Injection in HTTPS Admin Panel Delete Operations CVSS 3.1HIGH 7.2
- TI-2026-46994 Coturn: MOBILITY-TICKET session-resume authorization bypass allows cross-user TURN allocation takeover CVSS 3.1HIGH 7.1
Sources
- CVE-2026-73215 · CVE Program
- CVE-2026-73215 · NVD
- FIRST EPSS
- CVE-2026-73215 · Red Hat security data · CC BY 4.0
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