CVE-2026-48770: Notepad-Plus-Plus Notepad++

Medium severity, CVSS 5.0. EPSS: 0.1% chance of exploitation in the next 30 days.

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-Plus-Plus Notepad++: before 8.9.6.1 (fixed in 8.9.6.1)

Published 2026-06-26. Last modified 2026-06-29.