CVE-2026-52886

Notepad++: session.xml backupFilePath starts_with Bypass

MEDIUM
5.1
CVSS Score
Published: August 17, 2026 at 08:09 PM UTC
Updated: September 9, 2026 at 09:27 PM UTC
1 product affected across 1 vendorPlus Plus Notepad

Using notepad-plus-plus by notepad-plus-plus?

Get instant alerts when new vulnerabilities affect notepad-plus-plus - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM5.1
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 8.9.7
Affected range stops below 8.9.7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.1MEDIUMGitHub_M
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-22

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card