# CVE-2026-50198: Wallos: Cross-user subscription cost inference via replacement_subscription_id

> Authenticated users can infer other users' subscription costs by manipulating replacement IDs, exposing derived financial metadata.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A: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:** 31 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-hggr-v8rm-c6jj

## What is CVE-2026-50198?

CVE-2026-50198 is a medium-severity vulnerability in ellite Wallos, published on 31 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 4.9.1, an authenticated user can edit their own inactive subscription and set replacement_subscription_id to a subscription ID belonging to another user. The write is accepted, and later the stats logic dereferences that foreign subscription ID without user_id scoping. This lets the attacker infer the victim subscription's monthly-normalized cost by observing changes in their own stats output. This does not expose the full victim subscription object, but it does expose derived financial metadata. This issue has been patched in version 4.9.1.

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

## Which versions are affected by CVE-2026-50198?


## How do I fix CVE-2026-50198?

No fix has been published for CVE-2026-50198 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-50198 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-50198 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-50198 and fix it if it is affected.

What it is: CVE-2026-50198 is a medium-severity vulnerability in ellite Wallos, published on 31 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-50198 exists.

Affected product: ellite Wallos. 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-2026-50198/ (Markdown: https://insights.sbomify.com/CVE-2026-50198/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-50198
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-50198
- OSV: https://osv.dev/vulnerability/CVE-2026-50198

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-50198/
Summaries are generated and may contain mistakes; the official description above is the record.