CVE-2026-68553
Coturn: Format String Injection via TURN USERNAME/REALM into hiredis Redis Command
- State
- Published
- Severity
- 7.1 High
- Published
- Aug 19, 2026
- Updated
- Aug 20, 2026
- Reserved
- Jul 30, 2026
Description
Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.13.0, an authenticated TURN user can place printf-style format specifiers in the STUN USERNAME or REALM attribute, which passes is_secure_string() validation and is embedded into Redis keys at nine call sites in src/apps/relay/ns_ioalib_engine_impl.c. send_message_to_redis() in src/apps/relay/hiredis_libevent2.c then passes the attacker-controlled key as the format argument to redisAsyncCommand() while supplying only one variadic value, causing hiredis redisvFormatCommand() to read past the va_list. Exploitation can crash the coturn process and terminate active TURN sessions or disclose stack memory into Redis. This issue is fixed in version 4.13.0.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.1 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H | GitHub_M |
Weaknesses
- CWE-134 Use of Externally-Controlled Format String
Affected Products
| Product | Versions |
|---|---|
coturncoturn |
|
References
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