Rsyslog: mmpstrucdata stack buffer overflow with oversized RFC5424 structured data

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-61548
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-18 17:16:58 UTC
Updated2026-09-24 21:22:19 UTC
DescriptionRsyslog 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.

Risk And Classification

Primary CVSS: v3.1 8.1 HIGH from [email protected]

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

EPSS: 0.009400000 probability, percentile 0.592880000 (date 2026-09-25)

Problem Types: CWE-121 | CWE-121 CWE-121: Stack-based Buffer Overflow

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.1HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.1HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Rsyslog Rsyslog affected >= 7.5.4, < 8.2606.0 Not specified

References

ReferenceSourceLinkTags
github.com/rsyslog/rsyslog/security/advisories/GHSA-8qmr-c66f-g368 [email protected] github.com
github.com/rsyslog/rsyslog/commit/bcda60a3692efdf0c8e44102528f5a0ebe0dec6d [email protected] github.com
www.openwall.com/lists/oss-security/2026/07/20/1 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
github.com/rsyslog/rsyslog/pull/6991 [email protected] github.com
github.com/rsyslog/rsyslog/releases/tag/v8.2606.0 [email protected] github.com
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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