Cross-site Scripting in quill

published 2021-04-12 5 y ago modified 2026-06-17 4 mo ago also GHSA-4943-9vgg-gr5r , EUVD-2021-0933

cvss: 6.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.3%; EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits: 0; none known

A vulnerability in the HTML editor of Slab Quill 4.8.0 allows an attacker to execute arbitrary JavaScript by storing an XSS payload (a crafted onloadstart attribute of an IMG element) in a text field. Note: Researchers have claimed that this issue is not within the product itself, but is intended behavior in a web browser

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-07-19)

Exploit prediction

1.31% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

burninatorsec.blogspot.com https://burninatorsec.blogspot.com/2021/04/cve-2021-3163-xss-slab-quill-js.html referenced PoC, tagged "exploit" by a source, unverified
github.com https://github.com/quilljs/quill/issues/3364 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N
GitHub	3.1	4.2	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	quill	<=1.3.7	no fix listed

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

burninatorsec.blogspot.com /2021/04/cve-2021-3163-xss-slab-quill-js.html
web, exploit, third-party-advisory
github.com /quilljs/quill/issues/3364
web, exploit, issue-tracking, third-party-advisory
quilljs.com
web, product
github.com /quilljs/quill/issues/3273
web, broken-link, issue-tracking, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2021-3163
advisory
github.com /quilljs/quill/issues/3359
web
github.com /quilljs/quill
package

Sources

CVE List CVE-2021-3163
GitHub Advisory GHSA-4943-9vgg-gr5r
NVD CVE-2021-3163

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