CVE-2026-61548

CVE-2026-61548 · Rsyslog: mmpstrucdata stack buffer overflow with oversized RFC5424 structured data

This page contains facts from public vulnerability sources. Check the original advisory before updating.

Rsyslog is a rocket-fast system for log processing. From 7.5.4 until 8.2606.0, the optional mmpstrucdata plugin's parseSD_PARAM function in plugins/mmpstrucdata/mmpstrucdata.c stores RFC5424 parameter values in a fixed pVal[32 * 1024] stack buffer and calls parsePARAM_VALUE without supplying the destination size. A remote unauthenticated attacker whose crafted RFC5424 message reaches an action using mmpstrucdata can provide a structured-data parameter larger than that buffer when MaxMessageSize permits it, causing an attacker-controlled stack overwrite. Deployments that do not install and use the plugin, or whose effective message-size limit remains below the required threshold, are not affected by this issue. The demonstrated impact is a crash and interruption of log collection; code execution is not demonstrated. This issue is fixed in version 8.2606.0.

CVSS 8.1 · High · EPSS 0.9% · Fix available

Published

2026-09-18T16:54:28.925Z

Updated

2026-09-21T20:49:39.195Z

Stack: system

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