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Fencer Vulns
high 7.6

CVE-2026-53958 json

4gaBoards: SSO Pre-Account Takeover / Hijacking via Mass Assignment

published 2026-08-18 2 mo ago modified 2026-10-22 18 d ago also EUVD-2026-62203

cvss
7.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

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.

Patch / fix

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/RARgames/4gaBoards/security/advisories/GHSA-j2fw-r2gj-hfr3 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.6 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:L

Affected products

  • RARgames 4gaBoards

Classification

Weakness
  • CWE-287 Improper Authentication
  • CWE-915 Improperly Controlled Modification of Dynamically-Determined Object Attributes

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.