Skip to content
Fencer Intel
low 3.7

CVE-2026-126204 json

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

published 15d ago modified 12h ago also EUVD-2026-124641 , GHSA-j3cq-92fq-qg5f

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository express-rate-limit/express-rate-limit. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm express-rate-limit 8.7.2

Is CVE-2026-126204 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
12h ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-13).

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
npm express-rate-limit
<=8.7.1
8.7.2

Affected products

  • express-rate-limit express-rate-limit

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of express-rate-limit/express-rate-limit published their own advisory on GitHub. Reviewed sources take precedence over it.