How severe is CVE-2026-67334?

No CVSS score has been assigned to CVE-2026-67334 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-67334?

CVE-2026-67334 affects the following packages: better-auth (npm), @better-auth/scim (npm). Ecosystems affected: npm.

How do I fix CVE-2026-67334?

Update better-auth to 1.6.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-67334 is resolved across your whole dependency graph.

How do I detect CVE-2026-67334 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for better-auth, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-67334 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-67334 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-67334 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-67334?

CVE-2026-67334 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 24th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-67334?

CVE-2026-67334 is classified as CWE-459 (CWE-459). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-67334 published, and has it been updated?

CVE-2026-67334 was published on August 1, 2026 and was last updated on October 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-67334 — better-auth

CVE-2026-67334 is a CWE-459 vulnerability in better-auth. A fix is available for better-auth — see the affected versions and patch details below.

better-auth Stale Sessions Persist After User Deletion

Also known asGHSA-2vg6-77g8-24mp

Published

Aug 1, 2026

Updated

Oct 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 14, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-67334.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs24th percentile — riskier than 24% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

851other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

better-authnpm

11.9Mdownloads / week

@better-auth/scimnpm

212Kdownloads / week

Description

Am I affected?

Users are affected if all of the following are true:

They configure secondaryStorage on betterAuth(...) (Redis, KV, or any external session cache).
session.storeSessionInDatabase is left unset or set to false (the default).
Their application's deployment uses one or more of:
- The admin plugin and calls auth.api.removeUser(...) or authClient.admin.removeUser(...).
- The anonymous plugin and exposes /delete-anonymous-user or relies on the after-link hook to clean up the anonymous user.
- The @better-auth/scim plugin and exposes DELETE /scim/v2/Users/:userId.

If storeSessionInDatabase is true, sessions are also written to the database, and the database delete cascades; users are not affected.

Fix:

Upgrade to better-auth@<patched-version> or later (and @better-auth/scim@<patched-version> if they use SCIM).
If they cannot upgrade, see workarounds below.

Summary

When secondaryStorage is configured and storeSessionInDatabase is false, three user-deletion endpoints in better-auth plus one in @better-auth/scim call internalAdapter.deleteUser(userId) without first calling internalAdapter.deleteSessions(userId). The deleted user's session payload (which carries a cached user object) remains in secondary storage, and internalAdapter.findSession(token) keeps returning it as a valid session until the session TTL elapses (default 7 days).

Details

The vulnerable call sites are:

admin plugin's removeUser (packages/better-auth/src/plugins/admin/routes.ts:1463).
anonymous plugin's self-delete endpoint (packages/better-auth/src/plugins/anonymous/index.ts:222).
anonymous plugin's after-link hook (packages/better-auth/src/plugins/anonymous/index.ts:325).
@better-auth/scim's DELETE /scim/v2/Users/:userId (packages/scim/src/routes.ts:1019).

Working callers that already do the right thing: the core /delete-user self-delete and /delete-user/callback (packages/better-auth/src/api/routes/update-user.ts:551).

The fix shape extends each vulnerable caller to invoke deleteSessions(userId) before deleteUser(userId). The architectural follow-up centralizes the cleanup inside deleteUser itself or introduces a single deleteUserAndSessions orchestrator so future callers cannot regress this contract.

Patches

Fixed in better-auth@<patched-version> and @better-auth/scim@<patched-version>. All four user-deletion call sites now invoke deleteSessions(userId) before deleteUser(userId) so sessions are evicted from secondary storage at the same time the user row is removed.

Workarounds

If users cannot upgrade immediately:

Configuration-level: set session.storeSessionInDatabase: true. Subsequent user-delete writes reach the session table and the database cascade removes rows. Increases write volume for high-throughput sessions but eliminates the gap.
Code-level (admin path): when calling auth.api.removeUser, also call auth.api.revokeUserSessions({ body: { userId } }), which uses deleteSessions internally.
Code-level (SCIM path): wrap their SCIM provider's deprovisioning hook to call auth.api.revokeUserSessions(...) after the SCIM DELETE.
Code-level (anonymous path): in onLinkAccount, explicitly call internalAdapter.deleteSessions(anonymousUser.user.id) before allowing the new session to be issued.

Impact

Stale session validity: a deleted user's existing session cookie continues to authenticate against getSessionFromCtx until the session TTL elapses (default 7 days). Within that window, the deleted user retains their pre-existing read and write surface.
SCIM-driven deprovisioning gap: organizations using SCIM to revoke offboarded employees' access do not, in fact, revoke active sessions. The deleted account remains usable for up to 7 days after deprovisioning.

Credit

Reported by @iruizsalinas.

Resources

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`better-auth`	≥ 0.3.4&&< 1.6.11	1.6.11`npm install better-auth@1.6.11`
📦npm	`@better-auth/scim`	≥ 1.6.0&&< 1.6.11	1.6.11`npm install @better-auth/scim@1.6.11`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for better-auth, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update better-auth to 1.6.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-67334 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Am I affected? Users are affected if all of the following are true: - They configure `secondaryStorage` on `betterAuth(...)` (Redis, KV, or any external session cache). - `session.storeSessionInDatabase` is left unset or set to `false` (the default). - Their application's deployment uses one or more of: - The `admin` plugin and calls `auth.api.removeUser(...)` or `authClient.admin.removeUser(...)`. - The `anonymous` plugin and exposes `/delete-anonymous-user` or relies on the after-link hook to clean up the anonymous user. - The `@better-auth/scim` plugin and exposes `DELETE /scim/

O3 Security · Impact-Aware SCA

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