Is CVE-2026-30827 actively exploited?

No active exploitation of CVE-2026-30827 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-30827 be exploited remotely?

Yes. CVE-2026-30827 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-30827?

CVE-2026-30827 has a CVSS score of 7.5 (HIGH).

HOME VULNERABILITIESCVE-2026-30827

HIGH

CVE-2026-30827

CWE-770Published: March 7, 2026· Updated: Mar 11, 2026

7.5

CVSS v3.1

EPSS:0.01%probability of exploitation in 30 daysPercentile:2.0th

Official Description

express-rate-limit is a basic rate-limiting middleware for Express. In versions starting from 8.0.0 and prior to versions 8.0.2, 8.1.1, 8.2.2, and 8.3.0, the default keyGenerator in express-rate-limit applies IPv6 subnet masking (/56 by default) to all addresses that net.isIPv6() returns true for. This includes IPv4-mapped IPv6 addresses (::ffff:x.x.x.x), which Node.js returns as request.ip on dual-stack servers. Because the first 80 bits of all IPv4-mapped addresses are zero, a /56 (or any /32 to /80) subnet mask produces the same network key (::/56) for every IPv4 client. This collapses all IPv4 traffic into a single rate-limit bucket: one client exhausting the limit causes HTTP 429 for all other IPv4 clients. This issue has been patched in versions 8.0.2, 8.1.1, 8.2.2, and 8.3.0.

NVD Source

Technical Analysis

CVE-2026-30827 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.