PT-2026-23791 · Unknown · Express-Rate-Limit

Tinkanet · Published 2026-03-06 · Updated 2026-05-18 · CVE-2026-30827

Positive Technologies (AI Summary)

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions express-rate-limit versions 8.0.0 through 8.0.1 express-rate-limit versions 8.1.0 through 8.1.1 express-rate-limit versions 8.2.0 through 8.2.1

Description The default keyGenerator in express-rate-limit incorrectly applies IPv6 subnet masking to IPv4-mapped IPv6 addresses. This results in all IPv4 traffic being placed into a single rate-limit bucket. Consequently, a single client exhausting the rate limit can cause HTTP 429 errors for all other IPv4 clients. The issue occurs on Node.js dual-stack servers where request.ip contains IPv4-mapped IPv6 addresses. This affects the default keyGenerator configuration only. The issue can lead to a denial of service, as a single client can block all IPv4 traffic.

Recommendations Update to express-rate-limit version 8.0.2. Update to express-rate-limit version 8.1.1. Update to express-rate-limit version 8.2.2. Update to express-rate-limit version 8.3.0.

Exploit

Fix

Allocation of Resources Without Limits

Weakness Enumeration

CWE-770

Related Identifiers

CLEANSTART-2026-BE61221

CVE-2026-30827

GHSA-46WH-PXPV-Q5GQ

Affected Products

Express-Rate-Limit

References · 174

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/30xxx/CVE-2026-30827.json · Exploit
• https://github.com/express-rate-limit/express-rate-limit/commit/14e53888cdfd1b9798faf5b634c4206409e27fc4 · Patch
• https://github.com/express-rate-limit/express-rate-limit/security/advisories/GHSA-46wh-pxpv-q5gq · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-42036 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-44459 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-42035 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-6322 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-42338 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-30827 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-44455 · Security Note
• https://osv.dev/vulnerability/CVE-2026-30827 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-69873 · Security Note
• https://osv.dev/vulnerability/CLEANSTART-2026-BE61221 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-4926 · Security Note
• https://osv.dev/vulnerability/GHSA-46wh-pxpv-q5gq · Vendor Advisory