---
id: "CVE-2026-121550"
kind: "vulnerability"
aliases: ["CVE-2026-121550"]
title: "nnn: predictable FIFO path lets local users redirect file writes"
severity: "low"
cvss: 3.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["linux", "nnn", "package", "shared-systems"]
not_affected_if: ["nnn-newer-than-5.3", "single-user-machine"]
published_at: "2026-11-03T16:17:26+00:00"
first_seen_at: "2026-11-03T16:21:44+00:00"
updated_at: "2026-11-03T16:24:25+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121550", "first_seen_at": "2026-11-03T16:21:44+00:00"}]
---

# nnn: predictable FIFO path lets local users redirect file writes

nnn, a terminal file manager, accepts an existing NNN_FIFO path without checking it is a FIFO. A local attacker who pre-creates the predictable /tmp/nnn.fifo as a symlink can overwrite files the victim can write or learn which paths the victim browses.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `nnn -V` or `nnn --version` and compare against the versions in the sources
- Check whether the installed nnn is 5.3 or earlier

## Fix

- Patch linked from the NVD record (github.com); the fixed version is unknown from the sources

## Timeline

- 2026-11-03T16:21:44+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121550

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/nnn-through-5.3-symlink-following-write-via-nnn-fifo-handling
- [fix] Patch: github.com https://github.com/jarun/nnn/commit/04715921aece0257fef7a8558c0783493d98efff

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_