CVE-2026-52886Notepad++: session.xml backupFilePath starts_with Bypass

Description

Notepad++ is a free and open-source source code editor. Prior to 8.9.7, Notepad++ validates the backupFilePath attribute from session.xml with std::wstring::starts_with against the expected backup directory without path normalization, allowing parent-directory sequences during snapshot-mode restoration to read an arbitrary user-readable file outside the backup directory into an editor tab. This issue is fixed in version 8.9.7.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-rqfm-pw34-r7j6
• https://github.com/notepad-plus-plus/notepad-plus-plus/commit/7e66f36db666a13b09fb5c31232ab2ca1c2ebccc
• https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.7