Bug 2566011 (CVE-2026-121550)

Summary: CVE-2026-121550 nnn: nnn: arbitrary file overwrite via insecure FIFO path handling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: low    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in nnn. The application handles its communication path without verifying that an existing target is a legitimate first-in, first-out (FIFO) special file. A local attacker can exploit this issue by pre-creating the predictable file path as a symbolic link or regular file. This vulnerability allows the attacker to overwrite files writable by the targeted user or observe their directory browsing history.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2567205, 2567206    
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Description OSIDB Bzimport 2026-11-03 17:27:34 UTC 
nnn through 5.3 contains an insecure file handling vulnerability that allows local attackers to redirect writes because main() accepts an existing NNN_FIFO path without verifying it is a FIFO. Attackers can pre-create the documented predictable /tmp/nnn.fifo path as a symlink or readable regular file, causing victim-writable files to be overwritten or leaking the victim's browsed paths.