CVE-2021-3163
Cross-site Scripting in quill
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
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
- Record
CVE-2021-3163- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
CVE List No score
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
- Record
CVE-2021-3163- Updated
- 2026-11-02
EUVDEUVD-2021-0933 No score
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
- Record
EUVD-2021-0933- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4943-9vgg-gr5r
Cross-site Scripting in quill
A vulnerability in the HTML editor of Slab Quill allows an attacker to execute arbitrary JavaScript by storing an XSS payload (a crafted onloadstart attribute of an IMG element) in a text field. No patch exists and no further releases are planned.
This CVE is disputed. Researchers have claimed that this issue is not within the product itself, but is intended behavior in a web browser. More information can be found here.
- Record
GHSA-4943-9vgg-gr5r- CVSS 3.1
- 4.2 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVGHSA-4943-9vgg-gr5r
Cross-site Scripting in quill
A vulnerability in the HTML editor of Slab Quill allows an attacker to execute arbitrary JavaScript by storing an XSS payload (a crafted onloadstart attribute of an IMG element) in a text field. No patch exists and no further releases are planned.
This CVE is disputed. Researchers have claimed that this issue is not within the product itself, but is intended behavior in a web browser. More information can be found here.
- Record
GHSA-4943-9vgg-gr5r- CVSS 3.1
- 4.2 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
quillnpm |
through 1.3.7 | None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-3163 is a medium vulnerability (CVSS 6.1) in Slab Quill, published April 12, 2021. Its validity is disputed. EPSS puts the chance of exploitation in the next 30 days at 1.31%, the 70th percentile.
