fix: exclude image/svg+xml from default media upload allowlist - #2250
Draft
marcusbellamyshaw-cell wants to merge 1 commit into
Draft
fix: exclude image/svg+xml from default media upload allowlist#2250marcusbellamyshaw-cell wants to merge 1 commit into
marcusbellamyshaw-cell wants to merge 1 commit into
Conversation
GLOBAL_UPLOAD_ALLOWLIST used a bare "image/" prefix match, which unintentionally included image/svg+xml. There is no upload-time content validation for SVG, so a Contributor+ user could upload an SVG with an embedded <script>. Enumerate the safe raster types explicitly instead. Field-specific allowedMimeTypes overrides are unaffected. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
🦋 Changeset detectedLatest commit: 4b1d6ac The changes in this PR will be included in the next version bump. This PR includes changesets to release 17 packages
Not sure what this means? Click here to learn what changesets are. Click here if you're a maintainer who wants to add another changeset to this PR |
@emdash-cms/admin
@emdash-cms/auth
@emdash-cms/auth-atproto
@emdash-cms/blocks
@emdash-cms/cloudflare
@emdash-cms/contentful-to-portable-text
emdash
create-emdash
@emdash-cms/gutenberg-to-portable-text
@emdash-cms/plugin-cli
@emdash-cms/plugin-types
@emdash-cms/registry-client
@emdash-cms/registry-lexicons
@emdash-cms/registry-verification
@emdash-cms/sandbox-workerd
@emdash-cms/x402
@emdash-cms/plugin-ai-moderation
@emdash-cms/plugin-atproto
@emdash-cms/plugin-audit-log
@emdash-cms/plugin-color
@emdash-cms/plugin-embeds
@emdash-cms/plugin-field-kit
@emdash-cms/plugin-forms
@emdash-cms/plugin-webhook-notifier
commit: |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
What does this PR do?
Excludes
image/svg+xmlfrom the default media upload allowlist(
GLOBAL_UPLOAD_ALLOWLIST), which previously admitted it via a bare"image/"prefix match. There's no upload-time content validation for SVGanywhere in core, so a Contributor+ user could upload an SVG with an
embedded
<script>tag. The allowlist now enumerates the safe raster typesexplicitly (
image/png,image/jpeg,image/gif,image/webp) instead ofprefix-matching all of
image/*. Fields that explicitly configureimage/svg+xmlin their ownallowedMimeTypesare unaffected — this onlychanges the default fallback.
Found during a site-level pentest of an Emdash-based site (everybittexas.com)
— flagged as a Low-severity finding since the current serve-time route
already excludes SVG from
SAFE_INLINE_TYPES, forcingContent-Disposition: attachment+ a sandboxed CSP, so it wasn't directlyexploitable through the known serve path. Still worth closing at the
upload-time boundary rather than relying solely on serve-time headers as a
single point of failure. No related issue open upstream — filing directly.
Type of change
Checklist
pnpm typecheckpassespnpm lintpassespnpm testpasses (or targeted tests for my change)pnpm formathas been runAI-generated code disclosure
Screenshots / test output
New test
packages/core/tests/unit/media/media-allowlist.test.ts— 3 tests,confirms SVG rejected, PNG/JPEG/GIF/WebP/video/audio/PDF still allowed.
Full
tests/unit/media/**+ the twomedia-upload-*integration tests:14 files, 151 tests, all passing.