# CVE-2026-18386: Path traversal in WP BackItUp Community Edition

> Authenticated administrators can read arbitrary files on the server via a path traversal vulnerability in the backup_file parameter.

- **Severity:** Medium 4.9 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Sep 2026
- **Updated:** 10 Sep 2026
- **Also known as:** GHSA-6237-95m6-mmw4

## What is CVE-2026-18386?

CVE-2026-18386 is a medium-severity path traversal vulnerability in cssimmon WP BackItUp Community Edition, published on 10 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

The WP BackItUp Community Edition plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 2.1.0 via the 'backup_file' parameter parameter. This makes it possible for authenticated attackers, with administrator-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information. The basename() normalization present in the handler only executes when the traversed target path does not exist, providing no protection against reads of existing files.

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

## Which versions are affected by CVE-2026-18386?


## How do I fix CVE-2026-18386?

No fix has been published for CVE-2026-18386 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18386 being exploited?

There is no known exploitation of CVE-2026-18386 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18386 and fix it if it is affected.

What it is: CVE-2026-18386 is a medium-severity path traversal vulnerability in cssimmon WP BackItUp Community Edition, published on 10 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-18386 in the wild and no public exploit code.

Affected product: cssimmon WP BackItUp Community Edition. 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-2026-18386/ (Markdown: https://insights.sbomify.com/CVE-2026-18386/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18386
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18386
- OSV: https://osv.dev/vulnerability/CVE-2026-18386

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18386/
Summaries are generated and may contain mistakes; the official description above is the record.