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Fencer Vulns
high 8.1

CVE-2026-110863 json

Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers

published 2026-10-14 25 d ago modified 2026-10-16 23 d ago also EUVD-2026-101746

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits
0
none known

Summary

Better Auth @better-auth/sso from 1.7.0-rc.2 before 1.7.3 contains an authentication bypass vulnerability that allows authenticated users to sign in as other users by registering a personal SSO provider. Attackers can copy a legitimate provider's OIDC issuer or SAML entity ID and assert a victim's subject or NameID, because account lookup ignores providerId, creating sessions for victim accounts.

Patch / fix

  • better-auth sso 1.7.3

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-110863 updated cvss 8.1

@better-auth/sso: @better-auth/sso: Authentication bypass via personal SSO provider registration

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA 4.0 8.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • better-auth sso

Classification

Weakness

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.