CVE-2026-77605: Input Validation Flaw (CVSS 7.8)

Description

Notepad++ is a free and open-source source code editor. Prior to 8.9.8, the Folder as Workspace Run by system action in Notepad++ can resolve a different sibling file than the file selected by the user. When an attacker places a command script whose name is the selected text-file path with .cmd appended, and the user invokes Run by system on the text file on Windows 10 or Windows 11, Notepad++ can execute the sibling script as the current user instead of opening the selected file. This issue is fixed in version 8.9.8.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-20 Improper Input Validation

CWE-706 CWE-706

References

Other References

https://github.com/notepad-plus-plus/notepad-plus-plus/commit/00fa5df0da1d4f6b334317aa979db13ac77ee24d https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8 https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-w5xq-frjg-w4cw https://notepad-plus-plus.org/news/v898-released https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-w5xq-frjg-w4cw

Frequently Asked Questions

What is CVE-2026-77605? +

Notepad++ is a free and open-source source code editor. Prior to 8.9.8, the Folder as Workspace Run by system action in Notepad++ can resolve a different sibling file than the file selected by the user. When an attacker places a command script whose name is the selected text-file path with .cmd appended, and the user invokes Run by system on the text file on Windows 10 or Windows 11, Notepad++ can execute the sibling script as the current user instead of opening the selected file. This issue is fixed in version 8.9.8. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-77605? +

CVE-2026-77605 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-77605? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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