CVE-2026-5525 Stack-Based Buffer Overflow in Notepad++ File Drop Handler leads to DoS

Medium 6.0 Published 10 Apr 2026 Updated 10 Apr 2026

An attacker can cause a denial of service in Notepad++ by tricking a user into dragging and dropping a specifically crafted directory path.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-5525?

CVE-2026-5525 is a medium-severity memory corruption vulnerability in Notepad++, published on 10 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official description

A stack-based buffer overflow vulnerability exists in Notepad++ version 8.9.3 in the file drop handler component. When a user drags and drops a directory path of exactly 259 characters without a trailing backslash, the application appends a backslash and null terminator without proper bounds checking, resulting in a stack buffer overflow and application crash (STATUS_STACK_BUFFER_OVERRUN).

Weakness: CWE-121

Which versions are affected by CVE-2026-5525?

It affects 1 product.

Products include Notepad-Plus-Plus Notepad\+\+.

How do I fix CVE-2026-5525?

No fix has been published for CVE-2026-5525 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-5525 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-5525 exists.

Sources

Also known as GHSA-8hrp-2fqv-gvrx.