Answer in brief
CVE-2023-40013 records a Critical severity (CVSS 9.8) vulnerability in external-svg-loader Cross-site Scripting vulnerability. The current sources do not mark it as known exploited. The current feed maps external-svg-loader (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps external-svg-loader (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| external-svg-loadernpm | >=0 <1.6.9 | 1.6.9 |
Published upstream
Aug 14, 2023
Evidence: source:osv:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:recordFirst seen by HOL
Sep 10, 2026
### 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.
Quoted source text, attributed separately from HOL analysis.