CVE-2026-121550
nnn through 5.3 Symlink-Following Write via NNN_FIFO Handling
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.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| nnn jarun |
≥ 0; ≤ 5.3 (affected, custom)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 1.0 low |
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 3.3 low |
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N | CNA: VulnCheck |
| 4.0 / 1.0 low |
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD: [email protected] |
| 3.1 / 3.3 low |
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/jarun/nnn/issues/2188CNA: VulnCheck · issue-tracking
- https://github.com/jarun/nnnCNA: VulnCheck · product
- https://github.com/jarun/nnn/commit/04715921aece0257fef7a8558c0783493d98efffCNA: VulnCheck · patch
- https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L10635CNA: VulnCheck · technical-description
- https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L7433CNA: VulnCheck · technical-description
- https://www.vulncheck.com/advisories/nnn-through-5.3-symlink-following-write-via-nnn-fifo-handlingCNA: VulnCheck · third-party-advisory
- https://github.com/jarun/nnn[email protected]
- https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L10635[email protected]
- https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L7433[email protected]
- https://github.com/jarun/nnn/commit/04715921aece0257fef7a8558c0783493d98efff[email protected]
- https://github.com/jarun/nnn/issues/2188[email protected]
- https://www.vulncheck.com/advisories/nnn-through-5.3-symlink-following-write-via-nnn-fifo-handling[email protected]
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