Vulnerability · Published Nov 3, 2026 · Assigned by VulnCheck

CVE-2026-121550nnn through 5.3 Symlink-Following Write via NNN_FIFO Handling

Low 3.3

In plain English

A low-severity security flaw in nnn from jarun. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).

Severity (CVSS 3.1)3.3Low

Exploit odds (30 days)0.1%top 98.4% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	nnn	no fix listed	DEBIAN-CVE-2026-121550
Debian:13	nnn	no fix listed	DEBIAN-CVE-2026-121550
Debian:14	nnn	no fix listed	DEBIAN-CVE-2026-121550
Ubuntu:22.04:LTS	nnn	no fix listed	UBUNTU-CVE-2026-121550
Ubuntu:24.04:LTS	nnn	no fix listed	UBUNTU-CVE-2026-121550
Ubuntu:26.04:LTS	nnn	no fix listed	UBUNTU-CVE-2026-121550
Ubuntu:26.10	nnn	no fix listed	UBUNTU-CVE-2026-121550

Affected products (as reported)

Vendor	Product	Versions
jarun	nnn	0 – through 5.3

Weakness: CWE-59 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N

References

GitHub Issue #2188 issue-tracking
https://github.com/jarun/nnn product
Fix commit patch
https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L10635 technical-description
https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L7433 technical-description
VulnCheck Advisory: nnn through 5.3 Symlink-Following Write via NNN_FIFO Handling third-party-advisory