PT-2026-35729 · Gnu · Nano

Marcin Wyczechowski + 1 · Published 2026-04-28 · Updated 2026-04-29 · CVE-2026-40556

Positive Technologies (AI Summary)

CVSS v4.0

2.1

Low

Base vector

AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/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

Name of the Vulnerable Software and Affected Versions GNU nano versions prior to 9.0

Description GNU nano creates the user's ~/.local directory with overly permissive permissions when it does not already exist. During the first use of features requiring Cross-Desktop Group (XDG) data storage, the software requests directory mode 0777. In environments with a relaxed or zero umask (such as container environments, CI/CD runners, embedded systems, or shells configured with umask 000), this makes the directory world-writable. A local attacker can exploit a race window between the creation of ~/.local and the subsequent creation of more restrictive subdirectories to write controlled files into the victim's XDG directory hierarchy.

Recommendations Update to version 9.0.

Fix

Incorrect Permission

Weakness Enumeration

CWE-732

Related Identifiers

CVE-2026-40556

Affected Products

Nano

References · 10

• https://cgit.git.savannah.gnu.org/cgit/nano.git/commit/?id=cb43493e · Patch
• https://cve.org/CVERecord?id=CVE-2026-40556 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2026-40556 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-40556 · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-40556 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-40556 · Security Note
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-40556 · Vendor Advisory
• https://t.me/CVEtracker/52091 · Telegram Post
• https://cert.pl/en/posts/2026/04/CVE-2026-40556 · Note
• https://nano-editor.org · Note