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

> Attackers can read arbitrary user-readable files by manipulating session.xml backup paths, affecting Notepad++ users.

- **Severity:** Medium 5.1 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** GHSA-rqfm-pw34-r7j6

## What is CVE-2026-52886?

CVE-2026-52886 is a medium-severity path traversal vulnerability in notepad-plus-plus, published on 17 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### 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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-52886?


## How do I fix CVE-2026-52886?

No fix has been published for CVE-2026-52886 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-52886 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52886 exists.

Public exploit code:

- Notepad++ CVE-2026-52886 — session.xml backupFilePath starts_with() path traversal (GHSA-rqfm-pw34-r7j6) (github_poc): https://github.com/v3s9er/CVE-2026-52886

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52886 and fix it if it is affected.

What it is: CVE-2026-52886 is a medium-severity path traversal vulnerability in notepad-plus-plus, published on 17 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52886 exists.

Affected product: notepad-plus-plus. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-52886/ (Markdown: https://insights.sbomify.com/CVE-2026-52886/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52886
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52886
- OSV: https://osv.dev/vulnerability/CVE-2026-52886

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52886/
Summaries are generated and may contain mistakes; the official description above is the record.