CVE-2026-110864 better-auth CVE debrief

Who should care

Defenders responsible for Better Auth deployments, particularly those using versions 1.5.0-beta.12 to 1.7.6, should assess exposure and prioritize remediation or compensating controls.

Why it matters

The authentication bypass vulnerability in Better Auth 1.5.0-beta.12 before 1.7.7 allows unauthenticated attackers to sign in as other users, potentially leading to account takeover. Defenders should prioritize verifying exposure and remediation.

• Unauthenticated attackers can sign in as other users by forging encrypted profiles
• Account takeover is possible via implicit linking with a victim's verified email
• Verification of exposure and remediation priority is necessary for Better Auth deployments

Technical summary

The Better Auth OAuth Proxy plugin contains an authentication bypass vulnerability that allows unauthenticated attackers to sign in as other users by forging encrypted profiles when the proxy shares the global secret and cookie-stored state is used. This vulnerability affects Better Auth versions 1.5.0-beta.12 before 1.7.7. Defenders should prioritize verifying exposure of Better Auth versions 1.5.0-beta.12 to 1.7.6 and assessing the feasibility of upgrading to 1.7.7 or applying compensating controls. The CVE record and source item provide details on the authentication bypass vulnerability in Better Auth 1.5.0-beta.12 before 1.7.7.

Defensive priority

Defenders should prioritize verifying exposure of Better Auth versions 1.5.0-beta.12 to 1.7.6 and assessing the feasibility of upgrading to 1.7.7 or applying compensating controls.

Recommended defensive actions

• Verify exposure of Better Auth versions 1.5.0-beta.12 to 1.7.6
• Assess the feasibility of upgrading to 1.7.7
• Apply compensating controls to mitigate the authentication bypass vulnerability
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the authentication bypass vulnerability in Better Auth 1.5.0-beta.12 before 1.7.7. However, the corpus does not provide explicit information on exploitation or victim impact.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.