CVE-2026-111639 bbs-go through 4.4.6 Account Takeover via Google One Tap Login
Attackers can hijack user accounts in bbs-go by replaying Google ID tokens due to missing audience validation in the login endpoint.
- 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
- None listed
What is CVE-2026-111639?
CVE-2026-111639 is a high-severity authentication bypass vulnerability in mlogclub bbs-go, published on 16 Oct 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
bbs-go through 4.4.6 contains an authentication bypass vulnerability in the /api/login/google_one_tap endpoint that allows remote attackers to log in as other users by submitting Google ID tokens issued to any OAuth client. Attackers operating their own Google OAuth client can capture a victim's Google-signed ID token and replay it, since the aud claim is never checked, to obtain an authenticated session as the victim's Google-linked account.
Weakness: CWE-287
Which versions are affected by CVE-2026-111639?
How do I fix CVE-2026-111639?
No fix has been published for CVE-2026-111639 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-111639 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111639 exists.
Sources
Also known as GHSA-h5hh-rp4r-9p9x.