# CVE-2026-53647: FOSSBilling vulnerable to unauthenticated API key configuration disclosure via guest Serviceapikey get_info endpoint

> Unauthenticated access to the guest API endpoint allows retrieving sensitive custom configuration data from API keys, exposing business-sensitive information.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Jul 2026
- **Updated:** 7 Jul 2026
- **Also known as:** GHSA-737q-9gpr-6mpq

## What is CVE-2026-53647?

CVE-2026-53647 is a medium-severity vulnerability in FOSSBilling, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FOSSBilling is a free, open-source billing and client management system. In versions 0.5.3 through 0.7.2, the Guest `serviceapikey/get_info` API endpoint is accessible without authentication. Any caller with a valid API key can retrieve all custom configuration parameters (`custom_*` fields) stored in the key's database record. These custom fields are populated by billing administrators and can contain business-sensitive data such as pricing tiers, feature flags, rate limits, expiry overrides, or access scope data. Version 0.8.0 patches the issue. Some workarounds are available. Administrators can avoid storing sensitive data in `custom_*` API key configuration fields, monitor API logs for suspicious calls to `/api/guest/serviceapikey/get_info`, and/or disable the Serviceapikey module if not in active use.

Weakness: CWE-862 (Missing Authorization), CWE-306 (Missing Authentication for Critical Functionality), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-53647?


## How do I fix CVE-2026-53647?

No fix has been published for CVE-2026-53647 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53647 being exploited?

There is no known exploitation of CVE-2026-53647 in the wild and no public exploit code.

Public exploit code:

- FOSSBilling CVE-2026-53647 & CVE-2026-53646 PoC — Unauthenticated API key disclosure & password reset token reuse (github_poc): https://github.com/7megaumka7/FOSKiller

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53647 and fix it if it is affected.

What it is: CVE-2026-53647 is a medium-severity vulnerability in FOSSBilling, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53647 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-2026-53647/ (Markdown: https://insights.sbomify.com/CVE-2026-53647/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53647
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53647
- OSV: https://osv.dev/vulnerability/CVE-2026-53647

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53647/
Summaries are generated and may contain mistakes; the official description above is the record.