# CVE-2026-27708: FOSSBilling: IDOR in Servicecustom Client API allows cross-client data access

> Authenticated clients can access other users' sensitive data by guessing order IDs due to missing ownership checks in the API.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **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:** 24 Jun 2026
- **Updated:** 25 Jun 2026
- **Also known as:** GHSA-p36w-9x66-488j

## What is CVE-2026-27708?

CVE-2026-27708 is a high-severity missing authorization vulnerability in FOSSBilling, published on 24 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

FOSSBilling is a free, open-source billing and client management system. In versions 0.7.2 and prior, the Servicecustom Client API's __call method accepts an order_id parameter and fetches the associated order without verifying the authenticated client owns it, potentially exposing cross-client data through IDOR. An authenticated client can access any other client's custom service by guessing sequential order IDs. This can lead to a confidentiality breach — attackers can read client PII (name, email, phone, address, company details, VAT number) and service configuration data belonging to other clients. This issue has been fixed in version 0.8.0.

Weakness: CWE-862 (Missing Authorization), CWE-639 (Authorization Bypass Through User-Controlled Key), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-27708?


## How do I fix CVE-2026-27708?

No fix has been published for CVE-2026-27708 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-27708 being exploited?

There is no known exploitation of CVE-2026-27708 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-27708 and fix it if it is affected.

What it is: CVE-2026-27708 is a high-severity missing authorization vulnerability in FOSSBilling, published on 24 Jun 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-2026-27708 in the wild and no public exploit code.

Affected product: FOSSBilling. 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-2026-27708/ (Markdown: https://insights.sbomify.com/CVE-2026-27708/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-27708
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-27708
- OSV: https://osv.dev/vulnerability/CVE-2026-27708

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-27708/
Summaries are generated and may contain mistakes; the official description above is the record.