Vulnerability · Published Aug 17, 2026 · Assigned by GitHub_M

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

Medium 5.1

In plain English

A medium-severity path traversal in notepad-plus-plus from notepad-plus-plus. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.

Severity (CVSS 4.0)5.1Medium

Exploit odds (30 days)0.2%top 94.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack tooling1Public PoC

Official 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.

Affected products (as reported)

Vendor	Product	Versions
notepad-plus-plus	notepad-plus-plus	< 8.9.7

Weakness: CWE-22 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

References

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