What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-04-10 · updated 2026-10-26
• Weakness: CWE-121

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).

Affected products

• Notepad++: 8.9.3

References

• https://github.com/notepad-plus-plus/notepad-plus-plus/commit/bfe7514d68bc559534c046c4ef2d1865267aa2b0
• https://github.com/notepad-plus-plus/notepad-plus-plus/issues/17921
• https://github.com/notepad-plus-plus/notepad-plus-plus/pull/17930
• https://github.com/notepad-plus-plus/notepad-plus-plus/issues/17921

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