# CVE-2026-50191: 4gaBoards: Pre-Account Takeover via SSO Email Linkage

> Attackers can hijack victim accounts by pre-registering with their email, gaining access to projects and data upon the victim's first SSO login.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **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:** 18 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** GHSA-f3p6-chc6-pc77

## What is CVE-2026-50191?

CVE-2026-50191 is a high-severity authentication bypass vulnerability in RARgames 4gaBoards, published on 18 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

4gaBoards is a boards system for realtime project management. Prior to 3.3.8, 4gaBoards is vulnerable to pre-account takeover when registrationEnabled, localRegistrationEnabled, and ssoRegistrationEnabled are enabled and Google, GitHub, Microsoft, or OIDC SSO is configured. The POST /api/register endpoint permits creation of an unverified local account with a victim's email address, and POST /api/access-tokens permits that account to authenticate while isVerified is false. During the victim's first SSO login, server/api/helpers/users/get-create-one-for-github-sso.js, server/api/helpers/users/get-create-one-for-google-sso.js, server/api/helpers/users/get-create-one-for-microsoft-sso.js, and server/api/helpers/users/get-create-one-for-oidc-sso.js find the attacker-controlled account by email and link the verified SSO identity without confirming ownership of the local account. The attacker can retain local-password access to the linked account and obtain the victim's projects, data, and permissions. This issue is fixed in version 3.3.8.

Weakness: CWE-288 (Authentication Bypass Using an Alternate Path or Channel), CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-50191?


## How do I fix CVE-2026-50191?

No fix has been published for CVE-2026-50191 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-50191 being exploited?

There is no known exploitation of CVE-2026-50191 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-50191 and fix it if it is affected.

What it is: CVE-2026-50191 is a high-severity authentication bypass vulnerability in RARgames 4gaBoards, published on 18 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: There is no known exploitation of CVE-2026-50191 in the wild and no public exploit code.

Affected product: RARgames 4gaBoards. 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-2026-50191/ (Markdown: https://insights.sbomify.com/CVE-2026-50191/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-50191
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-50191
- OSV: https://osv.dev/vulnerability/CVE-2026-50191

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-50191/
Summaries are generated and may contain mistakes; the official description above is the record.