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CVE-2023-40013 — Vulnerability in external-svg-loader — CVE Details

CRITICAL

external-svg-loader Cross-site Scripting vulnerability

Published August 14, 2023Updated September 10, 2026Source: osv

Summary

### Summary According to the [docs](https://github.com/shubhamjain/svg-loader/tree/main#2-enable-javascript), svg-loader will strip all JS code before injecting the SVG file for security reasons but the input sanitization logic is not sufficient and can be trivially bypassed. This allows an attacker to craft a malicious SVG which can result in XSS. ### Details When trying to sanitize the svg the lib [removes event attributes](https://github.com/shubhamjain/svg-loader/blob/main/svg-loader.js#L125-L128) such as `onmouseover`, `onclick` but the list of events is not exhaustive. Here's a list of events not removed by svg-loader. `onafterscriptexecute, onbeforecopy, onbeforecut, onbeforescriptexecute, onbeforetoggle, onbegin, onbounce, onend, onfinish, onfocusin, onfocusout, onmousewheel, onpointerrawupdate, onrepeat, onsearch, onshow, onstart, ontoggle(popover), ontouchend, ontouchmove, ontouchstart` As you can see in the POC we can use `onbegin` in `animate` tag to execute JS code without needing to add `data-js="enabled"`. ### PoC ```html <svg version="1.1" baseProfile="full" xmlns="http://www.w3.org/2000/svg"> <animate onbegin=alert(1) attributeName=x dur=1s> </svg> ``` ```html <html> <head> <script src="./dist/svg-loader.js" type="text/javascript"></script> </head> <body> <svg data-src="data:image/svg+xml;base64,PHN2ZyB2ZXJzaW9uPSIxLjEiIGJhc2VQcm9maWxlPSJmdWxsIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPgogIDxwb2x5Z29uIGlkPSJ0cmlhbmdsZSIgcG9pbnRzPSIwLDAgMCw1MCA1MCwwIiBmaWxsPSIjMDA5OTAwIiBzdHJva2U9IiMwMDQ0MDAiLz4KICA8YW5pbWF0ZSBvbmJlZ2luPWFsZXJ0KDEpIGF0dHJpYnV0ZU5hbWU9eCBkdXI9MXM+Cjwvc3ZnPgo="></svg> </body> </html> ``` ### Impact Any website which uses external-svg-loader and allows its users to provide svg src, upload svg files would be susceptible to stored XSS attack.

Advisory Timeline

  • First published August 14, 2023 (1155 days ago).
  • Last revised September 10, 2026 — 1122 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

npm
Update external-svg-loader to 1.6.9 or later
npm install external-svg-loader@1.6.9

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (1)

Affects 1 ecosystem: npm (1).

PackageEcosystemAffectedFixed In
external-svg-loader
npm
All versions1.6.9

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

  • CWE-79
    Cross-site Scripting (XSS)MITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 9.8 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

References

Frequently Asked Questions

What is CVE-2023-40013?
external-svg-loader Cross-site Scripting vulnerability This vulnerability has been assigned a severity rating of CRITICAL (CVSS score: 9.8/10).
How do I check if my project is affected by CVE-2023-40013?
CVE-2023-40013 affects external-svg-loader. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2023-40013 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
9.8

Exploitation is straightforward and causes maximum impact. Patch immediately.

Also Known As

GHSA-xc2r-jf2x-gjr8

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