Improper Input Validation in is-email

published 2021-07-14 5y ago modified 2026-06-17 4mo ago also GHSA-j377-2x76-558h , EUVD-2021-2537

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.0%; EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits: 0; none known

A ReDoS (regular expression denial of service) flaw was found in the Segment is-email package before 1.0.1 for Node.js. An attacker that is able to provide crafted input to the isEmail(input) function may cause an application to consume an excessive amount of CPU.

Patch / fix

fixed in 2

npm is-email 1.0.1
segment is-email 1.0.1

Is CVE-2021-36716 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.

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Exploit prediction

0.99% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
npm	is-email	<1.0.1	1.0.1

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption
CWE-20 Improper Input Validation

References

segment.com /docs/release_notes/2021-07-13-cve-2021-36716/
vendor-advisory
github.com /segmentio/is-email/releases
web, release-notes, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2021-36716
advisory
github.com /segmentio/is-email
package
segment.com /docs/release_notes/2021-07-13-cve-2021-36716
web

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.