# CVE-2026-55439: Halo: Path Traversal in Backup Download Leads to Arbitrary File Read

> Authenticated administrators can read arbitrary files from the server filesystem via a path traversal vulnerability in the backup download endpoint.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Jun 2026
- **Updated:** 25 Jun 2026

## What is CVE-2026-55439?

CVE-2026-55439 is a medium-severity path traversal vulnerability in halo-dev halo, published on 25 Jun 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Halo is an open source website building tool. Prior to 2.24.3, a path traversal vulnerability in the backup download endpoint allows authenticated administrators to read arbitrary files from the server filesystem. The backup download endpoint (GET /apis/console.api.migration.halo.run/v1alpha1/backups/{name}/files/{filename}) in MigrationServiceImpl.download() resolves the backup filename via Path.resolve() without validating that the resolved path stays within the designated backups directory. Also, the Backup creation endpoint (POST /apis/migration.halo.run/v1alpha1/backups) does not sanitize the status fields during creation This vulnerability is fixed in 2.24.3.

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

## Which versions are affected by CVE-2026-55439?


## How do I fix CVE-2026-55439?

No fix has been published for CVE-2026-55439 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-55439 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55439 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55439 and fix it if it is affected.

What it is: CVE-2026-55439 is a medium-severity path traversal vulnerability in halo-dev halo, published on 25 Jun 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55439 exists.

Affected product: halo-dev halo. 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-2026-55439/ (Markdown: https://insights.sbomify.com/CVE-2026-55439/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55439
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55439
- OSV: https://osv.dev/vulnerability/CVE-2026-55439

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55439/
Summaries are generated and may contain mistakes; the official description above is the record.