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CVE-2026-30827

27
FAUCET Score

CVE-2026-30827 affects express-rate-limit versions 8.0.0 through 8.0.1, 8.1.0, 8.2.0, and 8.2.1. The vulnerability stems from the default keyGenerator incorrectly applying IPv6 subnet masking to IPv4-mapped IPv6 addresses, causing all IPv4 traffic to be grouped into a single rate-limit bucket on dual-stack servers. This allows a single IPv4 client to exhaust the rate limit, leading to a Denial of Service (DoS) for all other IPv4 clients. The vulnerability has a CVSS score of 7.5 (High), indicating a network-based attack with low complexity and high impact on availability. There is no authentication required, and no user interaction is needed for exploitation. There is no evidence of active exploitation, nor are there known Metasploit, Nuclei, or ExploitDB modules available. Community discussion is minimal, with only one mention identified. Patches are available in versions 8.0.2, 8.1.1, 8.2.2, and 8.3.0.

Impacted Technologies

VendorProductVersion(s)CPE
>= 8.0.0, < 8.0.2CPE matchmatch criteria
cpe:2.3:a:express-rate-limit_project:express-rate-limit:*:*:*:*:*:*:*:*
>= 8.2.0, < 8.2.2CPE matchmatch criteria
cpe:2.3:a:express-rate-limit_project:express-rate-limit:*:*:*:*:*:*:*:*
8.1.0CPE matchmatch criteria
cpe:2.3:a:express-rate-limit_project:express-rate-limit:8.1.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.46%
Probability of exploitation in next 30 days
EPSS Percentile
37.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0046 is in the 16th percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

npmpatch availablevia ghsa
Product: express-rate-limitFixed in: 8.2.2
npmpatch availablevia ghsa
Product: express-rate-limitFixed in: 8.1.1
npmpatch availablevia ghsa
Product: express-rate-limitFixed in: 8.0.2

Vendor Advisories (1)

npmGHSA-46wh-pxpv-q5gqhigh

express-rate-limit: IPv4-mapped IPv6 addresses bypass per-client rate limiting on servers with dual-stack network

Mar 6, 2026

References

github.com / express-rate-limit/express-rate-limit/commit/14e53888cdfd1b9798faf5b634c4206409e27fc4
Patch
github.com / express-rate-limit/express-rate-limit/security/advisories/GHSA-46wh-pxpv-q5gq
ExploitPatchVendor Advisory