express-rate-limit is a basic rate-limiting middleware for Express.
CVE-2026-126204
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.
Assessment
- CVSS
- 3.7 (v3.1)
- Severity
- Low
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 12 November 2026
- Last updated
- 12 November 2026
- Affected
- express-rate-limit · express-rate-limit
- Assigner
- GitHub_M
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
At the source
References
- https://github.com/express-rate-limit/express-rate-limit/security/advisories/GHSA-j3cq-92fq-qg5f
- https://github.com/express-rate-limit/express-rate-limit/pull/707
- https://github.com/express-rate-limit/express-rate-limit/commit/da5b115b97dd903076d37b19437fbd71445e150b
- https://github.com/express-rate-limit/express-rate-limit/releases/tag/v8.7.2
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