Log-service crash via oversized structured-data parameter
Published Sep 18, 2026 · Updated Sep 18, 2026
Stack overflow in rsyslog 7.5.4 and later, before 8.2606.0, allows remote attackers to crash logging via crafted RFC5424 messages. The mmpstrucdata parseSD_PARAM function gives parsePARAM_VALUE a fixed 32 KiB stack buffer without its size, so an oversized parameter overwrites the stack. Exposure requires the optional plugin to be installed and used, an effective MaxMessageSize above 32 KiB, and attacker-controlled structured data; demonstrated impact is a process crash that interrupts log collection.
Summary
What happened
Stack overflow in rsyslog 7.5.4 and later, before 8.2606.0, allows remote attackers to crash logging via crafted RFC5424 messages. The mmpstrucdata parseSD_PARAM function gives parsePARAM_VALUE a fixed 32 KiB stack buffer without its size, so an oversized parameter overwrites the stack. Exposure requires the optional plugin to be installed and used, an effective MaxMessageSize above 32 KiB, and attacker-controlled structured data; demonstrated impact is a process crash that interrupts log collection.
The record
- CVE
- CVE-2026-61548
- Published
- Sep 18, 2026
- Updated
- Sep 18, 2026
- Vendor
- rsyslog
- Product
- rsyslog
- Classifications
- CWE-121, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 18, 2026CVE publishedPublication date reported by the CVE source.
- Sep 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 7.5.4, < 8.2606.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Public exploit references
- Upstream mmpstrucdata crash proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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