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TI-2026-44103 Aliases CVE-2026-61548

Rsyslog: mmpstrucdata stack buffer overflow with oversized RFC5424 structured data

Priority LOW 38CWE-121Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-121 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00592 48th percentileScored 2026-11-07
Fix Fixed rsyslog (rsyslog): 8.2606.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
rsyslogrsyslog7.5.4 to before 8.2606.08.2606.0Patch availableCNA
  • rsyslog Vendorrsyslog Affected 7.5.4 to before 8.2606.0 Fixed in 8.2606.0 Patch available CNA

Remediation

  • Fix · CNA rsyslog (rsyslog) Fixed in 8.2606.0

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

Not affected: 5 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-61548
  2. 2026-11-02 EPSS moved to the below the 50th percentile

References

Other 4

  • TI-2026-40100 Rsyslog: Heap buffer overflow in imhttp plugin Basic Authentication handling CVSS 4.0HIGH 8.2
  • TI-2018-15792 rsyslog librelp version 1.2.14 and earlier contains a Buffer Overflow vulnerability in… CVSS 3.0CRITICAL 9.8
  • TI-2019-12711 An issue was discovered in Rsyslog v8.1908.0. CVSS 3.1CRITICAL 9.8
  • TI-2019-12712 An issue was discovered in Rsyslog v8.1908.0. CVSS 3.1CRITICAL 9.8
  • TI-2019-12710 contrib/pmdb2diag/pmdb2diag.c in Rsyslog v8.1908.0 allows out-of-bounds access because the level length is mishandled. CVSS 3.1CRITICAL 9.8
  • TI-2017-09315 The zmq3 input and output modules in rsyslog before 8.28.0 interpreted description fields… CVSS 3.0CRITICAL 9.8
See all 22 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences