{"id":"UBUNTU-CVE-2026-121550","details":"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.","modified":"2026-11-05T11:46:31.948215201Z","published":"2026-11-03T16:17:00Z","upstream":["CVE-2026-121550"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-121550"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-121550"},{"type":"REPORT","url":"https://github.com/jarun/nnn"},{"type":"REPORT","url":"https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L10635"},{"type":"REPORT","url":"https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L7433"},{"type":"REPORT","url":"https://github.com/jarun/nnn/commit/04715921aece0257fef7a8558c0783493d98efff"},{"type":"REPORT","url":"https://github.com/jarun/nnn/issues/2188"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/nnn-through-5.3-symlink-following-write-via-nnn-fifo-handling"}],"affected":[{"package":{"name":"nnn","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/nnn?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3-2","1.5-1","1.6-1","1.7-1"],"ecosystem_specific":{"binaries":[{"binary_name":"nnn","binary_version":"1.7-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-121550.json"}},{"package":{"name":"nnn","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/nnn?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.6-1","2.7-1","2.8-1","2.8.1-1","2.9-1","3.0-1","3.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"nnn","binary_version":"3.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-121550.json"}},{"package":{"name":"nnn","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/nnn?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.5-1","4.3-1"],"ecosystem_specific":{"binaries":[{"binary_name":"nnn","binary_version":"4.3-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-121550.json"}},{"package":{"name":"nnn","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/nnn?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.8-1","4.9-1","4.9-1build1","4.9-1build2"],"ecosystem_specific":{"binaries":[{"binary_name":"nnn","binary_version":"4.9-1build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-121550.json"}},{"package":{"name":"nnn","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/nnn?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.1-1","5.2-1","5.3-1"],"ecosystem_specific":{"binaries":[{"binary_name":"nnn","binary_version":"5.3-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-121550.json"}},{"package":{"name":"nnn","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/nnn?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.0-1","5.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"nnn","binary_version":"5.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-121550.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N"},{"type":"CVSS_V4","score":"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"},{"type":"Ubuntu","score":"medium"}]}