# CVE-2026-108109: PHPNuxBill through 2025.3.20 Account Takeover via Brute-Forceable Password Reset Code

> Unauthenticated attackers can hijack customer accounts by brute-forcing the 6-digit password reset code due to missing rate limits.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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:** 9 Oct 2026
- **Updated:** 9 Oct 2026
- **Also known as:** GHSA-337r-rrrc-r559, GHSA-mph9-7w43-p247

## What is CVE-2026-108109?

CVE-2026-108109 is a critical authentication bypass vulnerability in hotspotbilling phpnuxbill, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

PHPNuxBill through 2025.3.20 contains an account takeover vulnerability in the customer password reset flow in system/controllers/forgot.php that allows unauthenticated attackers to brute-force the 6-digit otp_code. Attackers knowing a customer username can guess the code without attempt limits or lockout, then read the newly set password from the HTTP response to hijack the account.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2026-108109?


## How do I fix CVE-2026-108109?

No fix has been published for CVE-2026-108109 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-108109 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-108109 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-108109 and fix it if it is affected.

What it is: CVE-2026-108109 is a critical authentication bypass vulnerability in hotspotbilling phpnuxbill, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-108109 exists.

Affected product: hotspotbilling phpnuxbill. 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-2026-108109/ (Markdown: https://insights.sbomify.com/CVE-2026-108109/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-108109
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-108109
- OSV: https://osv.dev/vulnerability/CVE-2026-108109

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-108109/
Summaries are generated and may contain mistakes; the official description above is the record.