# CVE-2026-100392: InvoicePlane: Primary Administrator Privilege Downgrade via `Users::form()` (Missing Object-Level Authorization)

> A secondary administrator can downgrade the primary administrator's privileges to guest, locking the owner out of the InvoicePlane instance.

- **Severity:** High 7.0 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/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:** 28 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-4fxw-x7wr-x6qc

## What is CVE-2026-100392?

CVE-2026-100392 is a high-severity missing authorization vulnerability in InvoicePlane, published on 28 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. In version 1.7.2, Users::form() performs no object-level authorization check on user_id = 1. A Secondary Administrator (user_type = 1, user_id != 1) can rewrite the Primary Administrator's user_type to 2 (Guest / read-only), destroying the root account's privilege and locking the legitimate owner out of the instance. At time of publication, there are no publicly available patches.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-100392?


## How do I fix CVE-2026-100392?

No fix has been published for CVE-2026-100392 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-100392 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100392 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-100392 and fix it if it is affected.

What it is: CVE-2026-100392 is a high-severity missing authorization vulnerability in InvoicePlane, published on 28 Sep 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-2026-100392 exists.

Affected product: InvoicePlane. 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-2026-100392/ (Markdown: https://insights.sbomify.com/CVE-2026-100392/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100392
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100392
- OSV: https://osv.dev/vulnerability/CVE-2026-100392

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-100392/
Summaries are generated and may contain mistakes; the official description above is the record.