Sanitizer: block data:/vbscript: URLs (XSS hardening)#42549
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The sanitizer's SAFE_URL_PATTERN only rejected javascript:, so a data:text/html (or vbscript:) URL in an href/src passed the allowList — an XSS vector via data-bs-title/data-bs-content. Reject data: and vbscript: in SAFE_URL_PATTERN and re-allow only safe base64 image/video/ audio data URLs via a restored DATA_URL_PATTERN. Fixes #42443.
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| * | ||
| * Shout-out to Angular https://github.com/angular/angular/blob/15.2.8/packages/core/src/sanitization/url_sanitizer.ts#L49 | ||
| */ | ||
| const DATA_URL_PATTERN = /^data:(?:image\/(?:bmp|gif|jpeg|jpg|png|tiff|webp)|video\/(?:mpeg|mp4|ogg|webm)|audio\/(?:mp3|oga|ogg|opus));base64,[\d+/a-z0-9=]+$/i |
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Problem (security)
The HTML sanitizer's
SAFE_URL_PATTERNonly rejectedjavascript:, so adata:text/html,…(orvbscript:) URL in anhref/srcpassed the attribute allowList. Viadata-bs-title/data-bs-content(withhtml: trueor a permissiveallowList) that's an XSS vector.Fix
SAFE_URL_PATTERNnow also rejectsdata:andvbscript:.DATA_URL_PATTERN(as in earlier Bootstrap) that re-allows only safe base64 image/video/audio data URLs, so legitimatedata:image/*sources keep working whiledata:text/htmlis blocked.Verification
data:text/html,…, base64text/html,vbscript:) to the sanitizer's invalid-URL test; existing validdata:image|video|audiobase64 URLs still pass.Fixes #42443.