Regular Expression Denial of Service (ReDoS)

published 2020-11-11 5 y ago modified 2026-06-17 4 mo ago also GHSA-cf2x-rqc8-grfq , EUVD-2021-1041

cvss: 5.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.6%; EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits: 0; none known

All versions of package express-validators are vulnerable to Regular Expression Denial of Service (ReDoS) when validating specifically-crafted invalid urls.

Exploit prediction

1.64% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

snyk.io https://snyk.io/vuln/SNYK-JS-EXPRESSVALIDATORS-1017404 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:U/RC:C
CNA	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem	package	affected	fixed in
npm	express-validators	<=1.0.4	no fix listed

Affected products

n/a express-validators

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption

References

snyk.io /vuln/SNYK-JS-EXPRESSVALIDATORS-1017404
web, exploit, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2020-7767
advisory

Sources

CVE List CVE-2020-7767
GitHub Advisory GHSA-cf2x-rqc8-grfq
NVD CVE-2020-7767

Fencer Vulns 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.

Summary