# CVE-2026-111367: BillionMail through 4.9 Forgeable JWTs via Default Signing Key

> Unauthenticated attackers can forge JWTs using a hard-coded key to modify contact subscriptions and bypass authentication in BillionMail.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/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:** 15 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-h86v-9fhw-gvch

## What is CVE-2026-111367?

CVE-2026-111367 is a medium-severity vulnerability in aaPanel BillionMail, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

BillionMail through 4.9 contains a hard-coded cryptographic key vulnerability that allows unauthenticated attackers to forge unsubscribe and subscribe-confirm JWTs by computing the key from shipped configuration constants. Attackers can submit forged tokens to /api/unsubscribe, /api/unsubscribe_new, or /api/subscribe/confirm to deactivate any contact or force confirmed subscriptions.

Weakness: CWE-1394 (Use of Default Cryptographic Key)

## Which versions are affected by CVE-2026-111367?


## How do I fix CVE-2026-111367?

No fix has been published for CVE-2026-111367 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-111367 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111367 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-111367 and fix it if it is affected.

What it is: CVE-2026-111367 is a medium-severity vulnerability in aaPanel BillionMail, published on 15 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-2026-111367 exists.

Affected product: aaPanel BillionMail. 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-2026-111367/ (Markdown: https://insights.sbomify.com/CVE-2026-111367/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-111367
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-111367
- OSV: https://osv.dev/vulnerability/CVE-2026-111367

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-111367/
Summaries are generated and may contain mistakes; the official description above is the record.