# CVE-2026-40556: nano vulnerability

CVE-2026-40556 is fixed in nano on 1 platform, first by DEBIAN-CVE-2026-40556, released May 15, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-40556
- Priority: Routine
- CVSS: n/a
- EPSS: n/a
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 28, 2026

## Description

This update for nano fixes the following issues:  Changes in nano:  - Update to version 9.1:   * When searching, the viewport is placed snug left where     possible.   * The ability to read and write files in old Mac format (a lone     carriage return as line ending) was removed.   * The ^T toggle between WhereIs and GotoLine was dropped.   * Fix backups that were missing or had a wrong timestamp when     --backup is active.   * On a crash or kill, a .save file is no longer chmodded or     chowned to the base file's permissions and owner.   * The history code now creates the ~/.local directory with     limited access rights (boo#1263437; the referenced     CVE-2026-40556 was rejected upstream).   * M-Ins and M-Del have become rebindable.  - GNU nano 9.0:   * When the cursor almost goes offscreen to the right, all lines     are now scrolled sideways together, by just the amount needed     to keep the cursor in view.     Use --solosidescroll or 'set solosidescroll' to get back the     old, jerky, single-line horizontal scrolling.   * The viewport can be scrolled sideways (in steps of one     tabsize) with M-< and M->.  See `man nanorc` if M-< and M->     should switch between buffers (as they did earlier).   * M-Left, M-Right, M-Up, and M-Down have become rebindable.   * Stopping the recording of a macro immediately after starting     it cancels the recording and leaves an existing macro in place.   * Feature toggles no longer break a chain of ^K cuts or M-6     copies, except the M-K cut-from-cursor toggle.   * With --mouse and --indicator, one can click in the scrollbar     area to roughly navigate within the buffer.   * CVE-2026-6843: format string vulnerability leads to denial of     service (boo#1262643)   * create the ~/.local directory with limited access rights     (CVE-2026-6842 boo#1263022, CVE-2026-40556 boo#1263437)  - GNU nano 8.7.1:   * fix build against glibc-2.43 (boo#1258260)  - GNU nano 8.7:   * At the Execute prompt, preceding the command with two pipe     symbols allows implementing a copy-to-clipboard feature in     nanorc on terminals that support OSC 52. See doc/sample.nanorc

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | nano Debian 14 | 9.0-1 | [DEBIAN-CVE-2026-40556](https://patchblox.com/security/data/fix/linux/debian-cve-2026-40556.md) | May 15, 2026 |
| Linux | nano opensuse-leap 16.0 | 9.1-bp160.1.1 | [OPENSUSE-SU-2026:21166-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21166-1.md) | Jun 29, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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