# CVE-2026-126204: express-rate-limit skipFailedRequests / skipSuccessfulRequests: with the default MemoryStore, a request from an earlier window is still un-counted from the current window

Status: published. Published: 2026-11-12. Updated: 2026-11-12.

express-rate-limit is a basic rate-limiting middleware for Express. From 8.6.0 until 8.7.2, the built-in MemoryStore returns a Client whose mutable resetTime object is retained by middleware using skipFailedRequests or skipSuccessfulRequests. When a later request resets the client window, MemoryStore.resetClient mutates that same Date, so an earlier request that finishes or disconnects after the reset can pass the stale-window guard and decrement the current window's count. A client able to keep requests in flight across the boundary can obtain a bounded extra burst of up to one additional configured limit in the new window; the behavior does not increase the sustained rate. Stores that return a fresh Date are not affected. This issue is fixed in version 8.7.2.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- express-rate-limit / express-rate-limit: >= 8.6.0, < 8.7.2 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 3.7 (low); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-682

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/express-rate-limit/express-rate-limit/security/advisories/GHSA-j3cq-92fq-qg5f (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/express-rate-limit/express-rate-limit/pull/707 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/express-rate-limit/express-rate-limit/commit/da5b115b97dd903076d37b19437fbd71445e150b (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/express-rate-limit/express-rate-limit/releases/tag/v8.7.2 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-126204; retrieved 2026-11-12; source updated 2026-11-12

Revision: e949ce492fa0cdaa18937fd57c1b7955b139ca4af02b4eafe3d63459d21c3662

Canonical: https://y2.dev/cve/CVE-2026-126204

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