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MEDIUM

CVE-2026-73212

CVE-2026-73212 — coturn peer-IP ACL canonicalization & scope bypass on the RFC 6062 TCP CONNECT relay path → internal-network SSRF and proven internal root RCE

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.13.1, good_peer_addr() in src/server/ns_turn_server.c uses ioa_addr_in_range() in src/client/ns_turn_ioaddr.c without canonicalizing IPv4-compatible, 6to4, and 64:ff9b::/96 NAT64 address forms, allowing an authenticated RFC 6062 TCP CONNECT relay client to bypass an IPv4 denied-peer-ip range when the Coturn host has a useful translation route. This issue is fixed in version 4.13.1.

Published Updated Sources: cvelistV5, GitHub_M

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

0%

chance of exploitation in 30 days

Affects

coturn

coturn

CVSS base

5.8

MEDIUM

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

No

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

coturn

Products (1)

coturn

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
5.8CVSS 4.0MEDIUM——cvelistV5

Weakness & attack patterns

  • CWE-284
  • CWE-918

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1027.009Obfuscated Files or Information: Embedded Payloads
  • T1546.004Event Triggered Execution: .bash_profile and .bashrc
  • T1546.016Event Triggered Execution: Installer Packages

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Search application, proxy, and WAF logs for requests touching /server/ns_turn_server.c, /client/ns_turn_ioaddr.c, /96.

References

6 on the record

Elsewhere on this site

  • coturnevery CVE for this vendor
  • CWE-284other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.