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.
- 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
- None listed
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.
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.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-53958 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53958 exists.
Sources
Also known as GHSA-j2fw-r2gj-hfr3.