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.

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Source ID Title
Ubuntu USN Ubuntu USN USN-8598-1 rsyslog vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 23 Sep 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-120
References
Metrics threat_severity

None

threat_severity

Important


Mon, 21 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Sun, 20 Sep 2026 04:30:00 +0000

Type Values Removed Values Added
First Time appeared Rsyslog
Rsyslog rsyslog
Vendors & Products Rsyslog
Rsyslog rsyslog

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Rsyslog: mmpstrucdata stack buffer overflow with oversized RFC5424 structured data
Weaknesses CWE-121
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-21T20:49:39.195Z

Reserved: 2026-07-10T16:27:03.094Z

Link: CVE-2026-61548

cve-icon Vulnrichment

Updated: 2026-09-18T17:11:33.491Z

cve-icon NVD

Status : Received

Published: 2026-09-18T17:16:58.190

Modified: 2026-09-21T21:17:06.633

Link: CVE-2026-61548

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-18T16:54:28Z

Links: CVE-2026-61548 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-23T16:30:08Z

Weaknesses