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
Description
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.
INFO
Published Date :
Nov. 12, 2026, 7:16 p.m.
Last Modified :
Nov. 12, 2026, 7:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | MITRE-CVE | ||||
| CVSS 3.1 | LOW | [email protected] |
Solution
- Update express-rate-limit to version 8.7.2.
- Use a date-immutable store if updating is not possible.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-126204.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-126204 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-126204
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-126204 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-126204 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Nov. 12, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-682 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/126xxx/CVE-2026-126204.json">CVE-2026-126204</a> Added Reference https://github.com/express-rate-limit/express-rate-limit/commit/da5b115b97dd903076d37b19437fbd71445e150b Added Reference https://github.com/express-rate-limit/express-rate-limit/pull/707 Added Reference https://github.com/express-rate-limit/express-rate-limit/releases/tag/v8.7.2 Added Reference https://github.com/express-rate-limit/express-rate-limit/security/advisories/GHSA-j3cq-92fq-qg5f