# CVE-2026-78381: RansomLook Arbitrary File Read via Path Traversal in Post screen Field

> An attacker with admin access or control over imported data can read arbitrary files via path traversal in the post screen field, exposing sensitive configuration and credentials.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Aug 2026
- **Updated:** 24 Aug 2026
- **Also known as:** GHSA-8f7x-5f58-rfpw

## What is CVE-2026-78381?

CVE-2026-78381 is a high-severity path traversal vulnerability in ransomlook, published on 24 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

RansomLook contains a path traversal vulnerability in the handling of the screen field associated with group posts. The GroupPost.get API handler concatenates the database-controlled screen value directly with the application's source/ directory and opens the resulting path without verifying that the resolved file remains within the intended directory.

Because the screen field is free-form and can be populated either through the administrative post editor or through data imported from a remote RansomLook instance, a malicious upstream instance can provide traversal sequences such as ../config/generic.json. When the affected post is subsequently retrieved through the API, RansomLook resolves and reads the attacker-controlled path and returns the contents of the referenced file Base64-encoded in the API response.

This can allow an attacker (being admin) controlling imported post data to read arbitrary files accessible to the RansomLook process, potentially exposing sensitive configuration data, API credentials, password hashes, or other application secrets. The attack does not require the malicious upstream to possess an account on the affected RansomLook instance.

The vulnerability is addressed by resolving screen paths with os.path.realpath() and verifying that the resolved path remains beneath the application's source/ directory. Validation is performed both when values are written and immediately before files are read. Using canonical paths also prevents traversal through symbolic links that would bypass purely lexical path normalization checks.

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

## Which versions are affected by CVE-2026-78381?


## How do I fix CVE-2026-78381?

No fix has been published for CVE-2026-78381 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-78381 being exploited?

There is no known exploitation of CVE-2026-78381 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78381 and fix it if it is affected.

What it is: CVE-2026-78381 is a high-severity path traversal vulnerability in ransomlook, published on 24 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-78381 in the wild and no public exploit code.

Affected product: ransomlook. 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-2026-78381/ (Markdown: https://insights.sbomify.com/CVE-2026-78381/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78381
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78381
- OSV: https://osv.dev/vulnerability/CVE-2026-78381

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78381/
Summaries are generated and may contain mistakes; the official description above is the record.