Better Auth drizzle-adapter 1.6.17 before 1.7.7 Rate Limit Bypass via Race Condition

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Better Auth @better-auth/drizzle-adapter and better-auth from 1.6.17 before 1.7.7, and @better-auth/kysely-adapter from 1.6.17 before 1.7.0, contain a race condition in database-backed rate limiting on PostgreSQL where the limit check is not atomic with the counter update. Remote attackers can send bursts of concurrent requests that pass the check together, exceeding configured limits on password sign-in, two-factor verification, one-time code, password reset, and other rate-limited endpoints.

Source published

14 Oct 2026 22:52:45 UTC

Source modified

20 Oct 2026 02:26:30 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 6.3 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS 3.1 · 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Better Auth @better-auth/drizzle-adapter and better-auth from 1.6.17 before 1.7.7, and @better-auth/kysely-adapter from 1.6.17 before 1.7.0, contain a race condition in database-backed rate limiting on PostgreSQL where the limit check is not atomic with the counter update. Remote attackers can send bursts of concurrent requests that pass the check together, exceeding configured limits on password sign-in, two-factor verification, one-time code, password reset, and other rate-limited endpoints.

Source published

Oct 14, 2026, 10:52:45 PM (timezone not stated)

Source modified

Oct 20, 2026, 2:26:30 AM (timezone not stated)

Observed here

30 Oct 2026 01:56:01 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 6.3 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Better Auth @better-auth/drizzle-adapter and better-auth from 1.6.17 before 1.7.7, and @better-auth/kysely-adapter from 1.6.17 before 1.7.0, contain a race condition in database-backed rate limiting on PostgreSQL where the limit check is not atomic with the counter update. Remote attackers can send bursts of concurrent requests that pass the check together, exceeding configured limits on password sign-in, two-factor verification, one-time code, password reset, and other rate-limited endpoints.

Source published

14 Oct 2026 23:17:27 UTC

Source modified

20 Oct 2026 03:17:14 UTC

Observed here

27 Oct 2026 16:45:50 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 6.3 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/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

CVSS 3.1 · [email protected] · Secondary · 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

## Am I affected? You are affected if you use `@better-auth/drizzle-adapter` from 1.6.17 through versions before 1.7.7 (including the 1.7.0 prereleases from beta.6 through rc.6) or `@better-auth/kysely-adapter` 1.6.17 through 1.6.31, and keep rate-limit records in a PostgreSQL database. All of these must be true: - Rate limiting is enabled. - Rate-limit records are stored in the database. - The database is PostgreSQL, used through one of the adapter versions above. You are not affected if you store rate-limit records in memory (the default) or in secondary storage. ## Summary Database-backed rate limiting on PostgreSQL can let a burst of concurrent requests go over the configured maximum. When many requests arrive at the same time, several of them can pass the limit check together. This weakens the rate limit on password sign-in, two-factor verification, one-time codes, password resets, and other rate-limited endpoints. ## Impact An attacker who sends many requests at once can make more attempts than the application allows. The issue does not bypass password or one-time-code validation. It does not directly compromise an account. The number of extra attempts is limited by the number of concurrent database connections, the number of application instances, and the rate-limit window. ## Patches `@better-auth/kysely-adapter` is fixed in 1.7.0. Upgrade to 1.7.0 or later. The Drizzle fix is merged for the planned `@better-auth/drizzle-adapter` 1.7.7 release. That package is not available yet. Upgrade `better-auth` and the installed Drizzle adapter together when 1.7.7 is available. No database schema or public API migration is required. ## Workarounds - Store rate-limit records in secondary storage. - Use a custom rate-limit storage that checks and increments the counter in one atomic step. An atomic step cannot be interrupted by another request. - Enforce the intended limit at an upstream layer, such as a reverse proxy or gateway. In-memory storage also avoids this issue. However, each application instance keeps its own counter, so it may not enforce one shared limit in multi-instance or serverless deployments.

Source published

27 Oct 2026 15:32:25 UTC

Source modified

27 Oct 2026 15:47:24 UTC

Observed here

27 Oct 2026 16:44:03 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Publisher rating · LOW