# CVE-2026-55610: InvoiceShelf has cross-company user read/update IDOR that enables cross-tenant account takeover

> Attackers can read and modify user accounts across different companies, leading to data disclosure and account takeover in multi-tenant installations.

- **Severity:** High 8.7 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Sep 2026
- **Updated:** 23 Sep 2026
- **Also known as:** GHSA-vgx6-6cqr-m8qr

## What is CVE-2026-55610?

CVE-2026-55610 is a high-severity missing authorization vulnerability in InvoiceShelf, published on 23 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

InvoiceShelf is an open-source web & mobile app that helps track expenses, payments and create professional invoices and estimates. Prior to version 2.4.1, in InvoiceShelf's multi-company installations, any user who is an Owner of one company can read and overwrite any user account in any other company on the same installation. `GET/PUT /api/v1/users/{user}` resolves the target `User` by global primary key, and `UserPolicy` checks only that the requester owns their own header-company — it never verifies that the target user belongs to that company. This allows cross-tenant disclosure of user data and full account takeover (email/password overwrite + company re-assignment). Version 2.4.1 fixes the issue.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-55610?


## How do I fix CVE-2026-55610?

No fix has been published for CVE-2026-55610 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-55610 being exploited?

There is no known exploitation of CVE-2026-55610 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55610 and fix it if it is affected.

What it is: CVE-2026-55610 is a high-severity missing authorization vulnerability in InvoiceShelf, published on 23 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-55610 in the wild and no public exploit code.

Affected product: InvoiceShelf. 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-2026-55610/ (Markdown: https://insights.sbomify.com/CVE-2026-55610/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55610
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55610
- OSV: https://osv.dev/vulnerability/CVE-2026-55610

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55610/
Summaries are generated and may contain mistakes; the official description above is the record.