CVE-2026-61548

HIGHPre-NVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.9%, top 41% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 4 sources updated this week
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.1Exploit: None knownExposed: 0

A fix is available — apply it.

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 v3
8.1
EG Score
8.1(medium)
EG Risk
37(Track)
EG Risk 37/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity81% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
59%
KEV
Not listed

Published

September 18, 2026

Last Modified

September 24, 2026

Advisory Details (4)

Auto-updated Sep 18, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

rsyslog 8.2606.0

Patch available: rsyslog/rsyslog v8.2606.0

https://github.com/rsyslog/rsyslog/releases/tag/v8.2606.0
github_commit Patch Available

commit bcda60a3692e (rsyslog/rsyslog)

Patch available: rsyslog/rsyslog v8.2606.0 (contains commit bcda60a3692e)

https://github.com/rsyslog/rsyslog/commit/bcda60a3692efdf0c8e44102528f5a0ebe0dec6d
github_pr Patch Available

mmpstrucdata: support custom SD containers

Patch available: rsyslog/rsyslog v8.2606.0 (PR #6991 merged 2026-06-02)

https://github.com/rsyslog/rsyslog/pull/6991
github Patch Available🟡 PoC Available

mmpstrucdata stack buffer overflow with oversized RFC5424 structured data · Advisory · rsyslog/rsyslog · GitHub

https://github.com/rsyslog/rsyslog/security/advisories/GHSA-8qmr-c66f-g368

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntursyslog-snmp (8.2512.0-1ubuntu4.1) @ resolute2026-09-25ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(2)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 29× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-25 10:10 UTCVendor advisory
  2. 2026-09-24 21:38 UTCEG score recompute
  3. 2026-09-24 21:38 UTCVendor advisory
  4. 2026-09-24 12:05 UTCVendor advisory
  5. 2026-09-23 23:33 UTCEG score recompute
  6. 2026-09-23 23:33 UTCVendor advisory
  7. 2026-09-23 17:54 UTCEPSS rescore
  8. 2026-09-23 11:01 UTCVendor advisory
  9. 2026-09-22 22:30 UTCEG score recompute
  10. 2026-09-22 22:30 UTCVendor advisory
  11. 2026-09-22 09:56 UTCVendor advisory
  12. 2026-09-21 21:24 UTCEG score recompute
  13. 2026-09-21 21:24 UTCVendor advisory
  14. 2026-09-21 20:58 UTCEG score recompute
  15. 2026-09-21 20:58 UTCVendor advisory
  16. 2026-09-21 09:06 UTCVendor advisory
  17. 2026-09-20 20:35 UTCEG score recompute
  18. 2026-09-20 20:35 UTCVendor advisory
  19. 2026-09-20 20:16 UTCEPSS rescore
  20. 2026-09-20 08:03 UTCVendor advisory
  21. 2026-09-19 19:31 UTCEG score recompute
  22. 2026-09-19 19:31 UTCVendor advisory
  23. 2026-09-19 06:59 UTCVendor advisory
  24. 2026-09-18 18:27 UTCEG score recompute
  25. 2026-09-18 18:27 UTCVendor advisory
Show 4 more
  1. 2026-09-18 17:19 UTCVendor advisory
  2. 2026-09-18 16:59 UTCEG score recompute
  3. 2026-09-18 16:59 UTCVendor advisory
  4. 2026-09-18 16:59 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-61548?
CVE-2026-61548 is a high vulnerability published on September 18, 2026. Rsyslog is a rocket-fast system for log processing. From 7.5.4 until 8.2606.0, the optional mmpstrucdata plugin's parseSDPARAM function in plugins/mmpstrucdata/mmpstrucdata.c stores RFC5424 parameter values in a fixed pVal[32 * 1024] stack buffer and calls parsePARAMVALUE without supplying the…
When was CVE-2026-61548 disclosed?
CVE-2026-61548 was first published in the National Vulnerability Database on September 18, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-61548 actively exploited?
CVE-2026-61548 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 40.8% of all scored CVEs.
What is the CVSS score of CVE-2026-61548?
CVE-2026-61548 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-61548?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-61548, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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