# CVE-2026-54599: Wallos: OIDC state parameter never validated — login CSRF / account takeover

> Attackers can force victims to log into attacker-controlled accounts via OIDC callback due to missing state validation, leading to account takeover.

- **Severity:** High 7.5 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 31 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-gr2w-m9v4-qm3v

## What is CVE-2026-54599?

CVE-2026-54599 is a high-severity vulnerability in ellite Wallos, published on 31 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 4.9.4, login.php generates an OIDC state nonce stored in $_SESSION['oidc_state'], but checksession.php dispatches the OIDC callback without comparing the incoming state against the session value. An attacker can trick a victim into visiting a crafted URL, causing Wallos to exchange the attacker's authorization code and log the victim into the attacker's account. This issue has been patched in version 4.9.4.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2026-54599?


## How do I fix CVE-2026-54599?

No fix has been published for CVE-2026-54599 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-54599 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54599 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54599 and fix it if it is affected.

What it is: CVE-2026-54599 is a high-severity vulnerability in ellite Wallos, published on 31 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54599 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-2026-54599/ (Markdown: https://insights.sbomify.com/CVE-2026-54599/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54599
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54599
- OSV: https://osv.dev/vulnerability/CVE-2026-54599

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54599/
Summaries are generated and may contain mistakes; the official description above is the record.