# CVE-2026-18636: Velociraptor VFSGetBuffer API path deny list bypass

> Attackers can bypass path restrictions in the VFSGetBuffer API to read sensitive files or access data from other organizations.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/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:** Yes
- **Published:** 11 Aug 2026
- **Updated:** 11 Aug 2026
- **Also known as:** GHSA-96p2-wv27-6pfj

## What is CVE-2026-18636?

CVE-2026-18636 is a medium-severity path traversal vulnerability in Rapid7 Velociraptor, published on 11 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

The Velociraptor gRPC API has a VFSGetBuffer endpoint which allows reading files from the datastore. To prevent users from reading sensitive files or accessing other orgs, the requested path is prefix checked against a list of denied prefixes. This prefix check can be bypassed allowing a user to access usually denied files. If the user has read permission in the ROOT org, this allows access to other orgs, in which the user may not have permission.

Weakness: CWE-288 (Authentication Bypass Using an Alternate Path or Channel)

## Which versions are affected by CVE-2026-18636?


## How do I fix CVE-2026-18636?

Apply the vendor's patch.

## Is CVE-2026-18636 being exploited?

There is no known exploitation of CVE-2026-18636 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18636 and fix it if it is affected.

What it is: CVE-2026-18636 is a medium-severity path traversal vulnerability in Rapid7 Velociraptor, published on 11 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-18636 in the wild and no public exploit code.

Affected product: Rapid7 Velociraptor. 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-2026-18636/ (Markdown: https://insights.sbomify.com/CVE-2026-18636/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18636
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18636
- OSV: https://osv.dev/vulnerability/CVE-2026-18636

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18636/
Summaries are generated and may contain mistakes; the official description above is the record.