Use of Externally-Controlled Format String Affecting coturn package, versions <4.14.0-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-COTURN-19166267
- published22 Aug 2026
- disclosed19 Aug 2026
Introduced: 19 Aug 2026
NewCVE-2026-68553 (opens in a new tab)How to fix?
Upgrade Debian:unstable coturn to version 4.14.0-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream coturn package and not the coturn package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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.