CVE-2026-48770

Notepad++ is a free and open-source source code editor. Prior to 8.9.6.1, a local process in the same interactive Windows session can send a malformed WM_COPYDATA message to Notepad++ using the COPYDATA_FULL_CMDLINE path. The handler appears to process COPYDATASTRUCT.lpData as an unbounded NUL-terminated wchar_t* instead of enforcing COPYDATASTRUCT.cbData. This vulnerability is fixed in 8.9.6.1.

Affected products

Notepad++

Notepad-plus-plus Notepad\+\+

< 8.9.6.1

Fix

Available

CVSS 3.1

5.0 MEDIUM

EPSS

0.1% (4th percentile)

Weakness

CWE-125

NVD status

Analyzed

Published

2026-06-26