{"id":"CVE-2026-68553","title":"Coturn is a free open source implementation of TURN and STUN Server","summary":"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…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H","cwe":["CWE-134"],"vendor":"coturn","product":"coturn","affected":["coturn < 4.13.0"],"published":"2026-08-19","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:20:38.860","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-68553","references":[{"url":"https://github.com/coturn/coturn/commit/8fa38032bb4751e11e072d65a8eca3c06c950979","label":"security-advisories@github.com"},{"url":"https://github.com/coturn/coturn/releases/tag/4.13.0","label":"security-advisories@github.com"},{"url":"https://github.com/coturn/coturn/security/advisories/GHSA-4g7c-p5wg-j4hp","label":"security-advisories@github.com"},{"url":"https://github.com/coturn/coturn/security/advisories/GHSA-4g7c-p5wg-j4hp","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-08-20T19:48:40.817549Z"},"ingestedAt":"2026-09-13T21:18:26.997Z","epss":0.0048,"epssPercentile":0.38718,"slug":"CVE-2026-68553","body":"## Overview\n\nCoturn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":51,"depthScoreParts":{"impact":39.1,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}