Bug 2566249 (CVE-2026-54161)

Summary: CVE-2026-54161 nut: nut: Arbitrary command execution via unsanitized alarm notifications in upsmon
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Network UPS Tools (NUT). An attacker capable of intercepting or controlling communications from an upstream server or monitored device can achieve arbitrary command execution with the privileges of the monitoring client, typically root. This issue occurs because the upsmon monitoring client incorporates server-supplied alarm messages directly into shell notification commands without adequate sanitization, allowing shell metacharacters to be executed.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-11-03 20:08:15 UTC 
Network UPS Tools is a collection of programs which provide a common interface for monitoring and administering UPS, PDU and SCD hardware. From 2.8.3 to 2.8.5, upsmon in clients/upsmon.c inserts the server-supplied ups.alarm value into shell commands executed by notify(), async_notify(), and wall(). When a monitored device reports an ALARM state and an operator has configured NOTIFYCMD with EXEC in NOTIFYFLAG ALARM, shell metacharacters in the alarm text are evaluated on POSIX or Windows and can execute arbitrary operating-system commands as the upsmon account, which is commonly root. An attacker can control the value through a malicious or compromised upsd, a man-in-the-middle on a plaintext upsd to upsmon connection, or a compromised UPS device whose driver supplies the alarm upstream of upsd; TLS between upsd and upsmon does not mitigate the compromised-device path. This vulnerability is fixed in 2.8.6.