CVE-2026-30827

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 62% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: Elevated riskExposed: 0

A fix is available — apply it.

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.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
39%
KEV
Not listed

Published

March 7, 2026

Last Modified

June 17, 2026

Advisory Details (2)

Auto-updated Aug 2, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available

IPv4-mapped IPv6 addresses bypass per-client rate limiting on servers with dual-stack network · Advisory · express-rate-limit/express-rate-limit · GitHub

https://github.com/express-rate-limit/express-rate-limit/security/advisories/GHSA-46wh-pxpv-q5gq
github_commit Patch Available

commit 14e53888cdfd (express-rate-limit/express-rate-limit)

Patch available: express-rate-limit/express-rate-limit v8.3.0 (contains commit 14e53888cdfd)

https://github.com/express-rate-limit/express-rate-limit/commit/14e53888cdfd1b9798faf5b634c4206409e27fc4

Vendor Advisories for CVE-2026-30827(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatdevspaces/openvsx-rhel9:17795282242026-05-28redhat
redhatansible-automation-platform-tech-preview/mcp-server-rhel9:17742681732026-04-01redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
express-rate-limit8.1.08.0.2—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 30× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 19:27 UTCEPSS rescore
  3. 2026-09-17 19:30 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-13 16:47 UTCEPSS rescore
  7. 2026-09-12 15:01 UTCEPSS rescore
  8. 2026-09-11 14:52 UTCEPSS rescore
  9. 2026-09-10 09:34 UTCEPSS rescore
  10. 2026-09-08 22:00 UTCEPSS rescore
  11. 2026-09-07 16:01 UTCEPSS rescore
  12. 2026-09-06 13:47 UTCEPSS rescore
  13. 2026-09-06 13:47 UTCEPSS rescore
  14. 2026-09-04 05:06 UTCEPSS rescore
  15. 2026-09-02 23:29 UTCOSV refresh
  16. 2026-09-02 14:11 UTCEPSS rescore
  17. 2026-09-01 13:53 UTCEPSS rescore
  18. 2026-09-01 04:39 UTCEPSS rescore
  19. 2026-09-01 04:39 UTCEPSS rescore
  20. 2026-08-30 19:17 UTCEPSS rescore
  21. 2026-08-30 01:22 UTCEPSS rescore
  22. 2026-08-28 21:41 UTCEPSS rescore
  23. 2026-08-27 14:25 UTCEPSS rescore
  24. 2026-08-26 14:46 UTCEPSS rescore
  25. 2026-08-25 13:49 UTCEPSS rescore
Show 55 more
  1. 2026-08-24 14:17 UTCEPSS rescore
  2. 2026-08-23 00:19 UTCEPSS rescore
  3. 2026-08-21 23:49 UTCEPSS rescore
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-20 22:55 UTCEPSS rescore
  6. 2026-08-19 17:03 UTCEPSS rescore
  7. 2026-08-18 13:48 UTCEPSS rescore
  8. 2026-08-17 13:47 UTCEPSS rescore
  9. 2026-08-16 14:56 UTCEPSS rescore
  10. 2026-08-16 12:18 UTCEG score recompute
  11. 2026-08-16 12:18 UTCVendor advisory
  12. 2026-08-16 02:14 UTCEPSS rescore
  13. 2026-08-15 01:30 UTCEPSS rescore
  14. 2026-08-14 20:50 UTCVendor advisory
  15. 2026-08-14 08:13 UTCEG score recompute
  16. 2026-08-14 08:13 UTCVendor advisory
  17. 2026-08-13 22:00 UTCEPSS rescore
  18. 2026-08-12 23:44 UTCEG score recompute
  19. 2026-08-12 23:44 UTCVendor advisory
  20. 2026-08-12 13:50 UTCEPSS rescore
  21. 2026-08-11 22:32 UTCEG score recompute
  22. 2026-08-11 22:32 UTCVendor advisory
  23. 2026-08-11 05:20 UTCEG score recompute
  24. 2026-08-11 05:20 UTCVendor advisory
  25. 2026-08-11 00:00 UTCEPSS rescore
  26. 2026-08-10 09:07 UTCVendor advisory
  27. 2026-08-09 20:30 UTCEG score recompute
  28. 2026-08-09 20:30 UTCVendor advisory
  29. 2026-08-09 13:46 UTCEPSS rescore
  30. 2026-08-09 07:53 UTCEG score recompute
  31. 2026-08-09 07:53 UTCVendor advisory
  32. 2026-08-08 16:37 UTCEPSS rescore
  33. 2026-08-08 07:56 UTCVendor advisory
  34. 2026-08-07 19:19 UTCEG score recompute
  35. 2026-08-07 19:19 UTCVendor advisory
  36. 2026-08-06 20:23 UTCEG score recompute
  37. 2026-08-06 20:23 UTCVendor advisory
  38. 2026-08-06 13:46 UTCEPSS rescore
  39. 2026-08-06 02:22 UTCEG score recompute
  40. 2026-08-06 02:22 UTCVendor advisory
  41. 2026-08-05 19:17 UTCEPSS rescore
  42. 2026-08-04 15:10 UTCEPSS rescore
  43. 2026-08-04 01:49 UTCEG score recompute
  44. 2026-08-04 01:49 UTCVendor advisory
  45. 2026-08-03 10:36 UTCEPSS rescore
  46. 2026-08-02 18:34 UTCEG score recompute
  47. 2026-08-02 18:34 UTCVendor advisory
  48. 2026-08-02 02:26 UTCEPSS rescore
  49. 2026-08-01 04:16 UTCEPSS rescore
  50. 2026-07-30 16:27 UTCEPSS rescore
  51. 2026-07-30 01:30 UTCEPSS rescore
  52. 2026-07-28 15:36 UTCEPSS rescore
  53. 2026-07-27 12:54 UTCEG score recompute
  54. 2026-07-27 12:54 UTCVendor advisory
  55. 2026-07-27 12:50 UTCOSV refresh

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-30827?
CVE-2026-30827 is a high vulnerability published on March 7, 2026. 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.…
When was CVE-2026-30827 disclosed?
CVE-2026-30827 was first published in the National Vulnerability Database on March 7, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-30827 actively exploited?
CVE-2026-30827 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 61.2% of all scored CVEs.
What is the CVSS score of CVE-2026-30827?
CVE-2026-30827 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-30827?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-30827, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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