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hyperframes/packages
Miguel Angel Simon Sierra b2ef6192ed fix(media-use): replace regex SVG sanitizer with a DOM allowlist
Two rounds of regex/tokenizer patches to sanitizeSvg found new bypasses
in the same shape each time (unquoted href, style= url(), aliased
xlink prefix; then presentation-attribute url(), unquoted '=' handling,
SMIL animate/set href rewrite, self-closing-slash tag corruption,
data:image/ navigation via <a>). Denylisting attribute names against a
hand-rolled tokenizer was the wrong approach regardless of how careful
the regex.

Rewrote sanitizeSvg (packages/core/src/figma/sanitizeSvg.ts) as a real
DOM walk (linkedom, already a dependency of core and cli) with an
allowlist: known-safe elements and attributes only, everything else
dropped by construction rather than pattern-matched as dangerous.
href/xlink:href (any namespace prefix) kept only for a same-document
fragment, or data:image/ off non-<a> elements. Any attribute value or
<style> text containing url() kept only when every url() argument is a
fragment; @import/expression(/javascript: dropped from style content.
Serializing from a real DOM means output is always well-formed, so the
self-closing-slash corruption class of bug is gone by construction.

media-use's own copy (packages/cli/src/media-use/lib/svg-sanitize.mjs)
can't import linkedom directly: its CI test lane runs bare `node --test`
with no install step, so even an external dependency fails to resolve,
not just a workspace import. It's now a generated file instead of a
hand-copy: scripts/generate-media-use-svg-sanitize.mjs bundles the core
source (esbuild, minified, zero remaining imports) and
scripts/check-media-use-svg-sanitize-generated.test.mjs fails the build
on drift. Verified the generated file runs with plain node in an empty
directory with no node_modules on the path.

Every payload from both independent-review reports is now a
table-driven test in sanitizeSvg.test.ts (46 cases) and the same corpus
in check-svg-sanitize-parity.test.mjs (39 cases) asserts core and the
generated media-use copy agree and each independently rejects every
non-local url(), javascript:, data: href on <a>, and on* handler.
Mutation-proved against the real pre-fix blob, not a synthetic case.

Sampled 56 real theSVG icons across all 7 collections to check the
allowlist doesn't over-strip legitimate content: found and fixed three
missing attributes (fx/fy, enable-background, a blanket data-*
allowance) and one real behavioral bug - <style> elements were being
dropped outright, silently unstyling any Illustrator-exported logo that
colors paths via CSS classes. Fixed by keeping <style> on the allowlist
and content-checking its text the same way as an inline style=
attribute, with a regression test using that exact shape.

Full suite after the fix: sanitizeSvg.test.ts 46/46, parity+drift tests
39/39, media-use suite 298/298, tsc/oxlint/oxfmt clean.
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