CVE-2026-40556
Insecure Directory Permissions in GNU nano Leading to Privilege Abuse
Description
Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.
INFO
Published Date :
April 28, 2026, 3:16 p.m.
Last Modified :
April 29, 2026, 8:16 a.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | LOW | 4bb8329e-dd38-46c1-aafb-9bf32bcb93c6 | ||||
| CVSS 4.0 | LOW | [email protected] |
Solution
- Update nano to version 9.0 or higher.
- Verify and correct ~/.local directory permissions.
- Ensure restrictive umask settings are applied.
- Review container and CI/CD configurations.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-40556 vulnerability anywhere in the article.
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cert.pl
Vulnerability in GNU nano software
Vulnerability in GNU nano software CVE ID CVE-2026-40556 Publication date 28 April 2026 Vendor GNU Product nano Vulnerable versions From 2.9.1 below 9.0 Vulnerability type (CWE) Incorrect Permission A ... Read more
The following table lists the changes that have been made to the
CVE-2026-40556 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Rejected by [email protected]
Apr. 29, 2026
Action Type Old Value New Value -
CVE Modified by [email protected]
Apr. 29, 2026
Action Type Old Value New Value Changed Description GNU nano creates the user’s ~/.local directory with overly permissive permissions when the directory does not exist yet. On first use of features requiring Cross-Desktop Group (XDG) data storage, nano explicitly requests directory mode 0777, making the directory world‑writable in environments where the process umask does not sufficiently restrict permissions. In systems with a relaxed or zero umask, such as container environments, CI/CD runners, embedded systems, or user shells configured with umask 000, this results in ~/.local being created as world‑writable. A local attacker can exploit a race window between nano’s creation of ~/.local and its subsequent creation of more restrictive subdirectories to write attacker‑controlled files into the victim’s XDG directory hierarchy. This problem was fixed in nano version 9.0 Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority. Removed CVSS V4.0 CERT.PL: 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 Removed CWE CERT.PL: CWE-732 Removed Reference CERT.PL: https://cert.pl/en/posts/2026/04/CVE-2026-40556/ Removed Reference CERT.PL: https://cgit.git.savannah.gnu.org/cgit/nano.git/commit/?id=cb43493e Removed Reference CERT.PL: https://www.nano-editor.org/ -
New CVE Received by [email protected]
Apr. 28, 2026
Action Type Old Value New Value Added Description GNU nano creates the user’s ~/.local directory with overly permissive permissions when the directory does not exist yet. On first use of features requiring Cross-Desktop Group (XDG) data storage, nano explicitly requests directory mode 0777, making the directory world‑writable in environments where the process umask does not sufficiently restrict permissions. In systems with a relaxed or zero umask, such as container environments, CI/CD runners, embedded systems, or user shells configured with umask 000, this results in ~/.local being created as world‑writable. A local attacker can exploit a race window between nano’s creation of ~/.local and its subsequent creation of more restrictive subdirectories to write attacker‑controlled files into the victim’s XDG directory hierarchy. This problem was fixed in nano version 9.0 Added CVSS V4.0 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 Added CWE CWE-732 Added Reference https://cert.pl/en/posts/2026/04/CVE-2026-40556/ Added Reference https://cgit.git.savannah.gnu.org/cgit/nano.git/commit/?id=cb43493e Added Reference https://www.nano-editor.org/