Stack-based buffer overflow in rsyslog mmpstrucdata module (CVE-2026-61548)

A stack-based buffer overflow exists in rsyslog's optional mmpstrucdata module, where parseSD_PARAM() allocates a fixed 32,768-byte stack buffer and passes it to parsePARAM_VALUE() without a size bound, allowing attacker-controlled input to overwrite the stack. A remote, unauthenticated attacker able to send crafted RFC 5424 messages through an input path processed by mmpstrucdata can crash the rsyslog process, causing denial of service and interruption of log collection; code execution may be possible on some platforms depending on build hardening. Affected versions: - rsyslog 7.5.4 and later, before 8.2606.0 We recommend updating to: rsyslog 8.2606.0. CVSS ? · our assessment: act_now Reference: https://seclists.org/oss-sec/2026/q3/173 Details: https://vuln.today/cve/CVE-2026-61548