---
cve: "CVE-2026-68553"
severity: "HIGH"
cvss: 7.1
epss: "35%"
vendor: "coturn"
kev: false
exploited: false
published: "2026-08-19 21:17:28"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T03:03:15+02:00"
---

# CVE-2026-68553

> 7.1 HIGH · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Gering | warn |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- 8fa38032bb4751e11e072d65a8eca3c06c950979 (Commit)
- bd02141ad865830fdea420ca0c803edf5ba8240c (Commit)

## Referenzen

- <https://github.com/coturn/coturn/security/advisories/GHSA-4g7c-p5wg-j4hp>
- <https://github.com/coturn/coturn/commit/8fa38032bb4751e11e072d65a8eca3c06c950979>
- <https://github.com/coturn/coturn/releases/tag/4.13.0>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-68553) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_