CVE-2026-111639
highpriority · track · 32EPSS 0.004 · 31 %ileEPSS · scored 2026-10-24
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.2–8.6
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products
Products and version ranges known to be affected.
No affected products recorded.
sources
Which sources assert this record, and when.
references (4) nvd
External citations — patches, advisories, analysis.
- https://github.com/mlogclub/bbs-go/blob/v4.4.6/internal/pkg/google/jwt.go#L55-L58
- https://github.com/mlogclub/bbs-go/blob/v4.4.6/internal/services/third_user_service.go#L274-L293
- https://hackmd.io/@hieuPenguinnn/bbs-go-google-one-tap-id-token-audience-confusion-account-takeover
- https://www.vulncheck.com/advisories/bbs-go-through-4.4.6-account-takeover-via-google-one-tap-login
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