# CVE-2026-56843: Missing authorization in Plesk

> Low-privileged users can bypass authorization to view other tenants' cleartext FTP credentials, enabling cross-tenant code execution.

- **Severity:** Critical 9.9 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Jul 2026
- **Updated:** 8 Jul 2026
- **Also known as:** GHSA-m4rp-7vj2-ggpc

## What is CVE-2026-56843?

CVE-2026-56843 is a critical missing authorization vulnerability in Webpros Plesk, published on 8 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Incorrect authorization in the XML-RPC API of WebPros Plesk before 18.0.78.4 allows a low-privileged authenticated customer to look up domains they do not own, because ownership is enforced only for certain lookup filters and schema validation is bypassed for legacy protocol versions. This results in cross-tenant disclosure of other tenants' FTP credentials stored in cleartext, which can be leveraged to execute code as another tenant's system user.

Weakness: CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2026-56843?


## How do I fix CVE-2026-56843?

No fix has been published for CVE-2026-56843 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-56843 being exploited?

There is no known exploitation of CVE-2026-56843 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56843 and fix it if it is affected.

What it is: CVE-2026-56843 is a critical missing authorization vulnerability in Webpros Plesk, published on 8 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-56843 in the wild and no public exploit code.

Affected product: Webpros Plesk. 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-2026-56843/ (Markdown: https://insights.sbomify.com/CVE-2026-56843/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56843
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56843
- OSV: https://osv.dev/vulnerability/CVE-2026-56843

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56843/
Summaries are generated and may contain mistakes; the official description above is the record.