# CVE-2026-53958: 4gaBoards: SSO Pre-Account Takeover / Hijacking via Mass Assignment

> Authenticated users can hijack victim accounts via mass assignment of SSO identifiers, leading to unauthorized access to victim data.

- **Severity:** High 7.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **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-j2fw-r2gj-hfr3

## What is CVE-2026-53958?

CVE-2026-53958 is a high-severity missing authorization vulnerability in RARgames 4gaBoards, published on 18 Aug 2026. Any signed-in user can exploit it over the network, 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 3.3.9, 4gaBoards allows an authenticated user to modify ssoGoogleId, ssoGoogleEmail, ssoGithubId, ssoGithubUsername, ssoGithubEmail, ssoMicrosoftId, ssoMicrosoftEmail, ssoOidcId, and ssoOidcEmail through PATCH /api/users/:id. The whitelist in server/api/controllers/users/update.js mass assigns these backend-managed identity attributes from user input. An attacker can place a victim's provider identifier on an attacker-controlled account, causing the default lookup in helpers such as server/api/helpers/users/get-create-one-for-github-sso.js to match the victim's first SSO login to the attacker's account before the email-linkage flow runs. The victim is logged into the attacker-controlled account, and projects, boards, or data the victim creates remain accessible through the attacker's original local credentials. This issue is fixed in version 3.3.9.

Weakness: CWE-915 (Improperly Controlled Modification of Dynamically-Determined Object Attributes), CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-53958?


## How do I fix CVE-2026-53958?

No fix has been published for CVE-2026-53958 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53958 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53958 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53958 and fix it if it is affected.

What it is: CVE-2026-53958 is a high-severity missing authorization vulnerability in RARgames 4gaBoards, published on 18 Aug 2026. Any signed-in user can exploit it over the network, 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-2026-53958 exists.

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-2026-53958/ (Markdown: https://insights.sbomify.com/CVE-2026-53958/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53958
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53958
- OSV: https://osv.dev/vulnerability/CVE-2026-53958

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53958/
Summaries are generated and may contain mistakes; the official description above is the record.