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Ubuntu 26.04 Rsyslog Critical Denial of Service Vuln USN-8598-1

ubuntu
Calendar Grey July 23, 2026
Scroller Ubuntu
Several critical security issues are fixed in rsyslog on Ubuntu including potential denial of service risks.
Ubuntu Security Notice USN-8598-1 addresses vulnerabilities in rsyslog affecting multiple versions of Ubuntu, which could allow remote attackers to cause denial of service

Summary

Several security issues were fixed in rsyslog.

Software Description:

- rsyslog: Enhanced syslogd

Details:

It was discovered that rsyslog incorrectly handled regex-based TCP framing

in the imptcp module. A remote attacker could possibly use this issue to

cause rsyslog to crash, resulting in a denial of service.

It was discovered that rsyslog incorrectly handled oversized RFC5424

structured data in the mmpstrucdata module. A remote attacker could

possibly use this issue to cause rsyslog to crash, resulting in a denial of

service. (CVE-2026-61548)

Topics%20covered

Topics Covered

security advisory denial of service security issue critical Ubuntu rsyslog

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 26.04 LTS
  rsyslog                         8.2512.0-1ubuntu4.1

Ubuntu 24.04 LTS
  rsyslog                         8.2312.0-3ubuntu9.3

Ubuntu 22.04 LTS
  rsyslog                         8.2112.0-2ubuntu2.4

In general, a standard system update will make all the necessary changes.

References

https://ubuntu.com/security/notices/USN-8598-1

CVE-2026-61548

Severity
critical
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8598-1

Topics%20covered

Topics Covered

security advisory denial of service security issue critical Ubuntu rsyslog

Package Information

https://launchpad.net/ubuntu/+source/rsyslog/8.2512.0-1ubuntu4.1
https://launchpad.net/ubuntu/+source/rsyslog/8.2312.0-3ubuntu9.3
https://launchpad.net/ubuntu/+source/rsyslog/8.2112.0-2ubuntu2.4

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