Stack Buffer Overflow in Rsyslog Due to mmpstrucdata Plugin Vulnerability

CVE-2026-61548

What is CVE-2026-61548?

The mmpstrucdata plugin in Rsyslog versions 7.5.4 to 8.2606.0 contains a flaw in the parseSD_PARAM function, leading to a potential stack buffer overflow. An attacker could exploit this vulnerability by sending a crafted RFC5424 message with a structured-data parameter that exceeds the allocated buffer size. If the MaxMessageSize setting permits, this could result in a remote unauthenticated attacker causing a stack overwrite, leading to log collection disruptions. The issue has been resolved in version 8.2606.0, emphasizing the importance of keeping software updated.

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