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Update source-map-js to patched release - #523

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realjkg merged 2 commits into
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copilot/fix-source-map-js-vulnerability-again
Oct 8, 2026
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realjkg merged 2 commits into
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copilot/fix-source-map-js-vulnerability-again

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Copilot AI commented Oct 8, 2026 •

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The demo lockfile resolved vulnerable source-map-js@1.2.1, which can block the event loop when parsing indexed source maps with extreme section offsets.

  • Dependency update: Lock source-map-js@1.2.2 in both frontend npm lockfiles, the lowest patched release.
  • Reachability: Not reachable at runtime (high confidence). The package is used by build-time PostCSS tooling; application code does not call its source-map APIs or process attacker-controlled indexed maps.
Original prompt

This section details the Dependabot vulnerability alert you should resolve

<alert_title>source-map-js allows event-loop denial of service through indexed source-map section offsets</alert_title>
<alert_description>source-map-js through 1.2.1 fails to validate the per-section offset line value in indexed source maps, allowing attackers to specify arbitrary numeric values. Attackers can supply extremely large offset line values that cause synchronous event loop blocking for extended periods, preventing the service from handling other requests.</alert_description>

high
GHSA-68fv-2mgg-jv7q, CVE-2026-93749
source-map-js
npm
<vulnerable_versions>1.2.1</vulnerable_versions>
<patched_version>1.2.2</patched_version>
<manifest_path>demo/package-lock.json</manifest_path>

https://nvd.nist.gov/vuln/detail/CVE-2026-93749 https://github.com/7rulnik/source-map-js/issues/76 https://github.com/7rulnik/source-map-js https://github.com/7rulnik/source-map-js/blob/c1cd8904bb7bd0c7fb5879fcda48134d82a27934/lib/source-node.js#L115-L118 https://www.vulncheck.com/advisories/source-map-js-through-1.2.1-event-loop-denial-of-service https://github.com/7rulnik/source-map-js/pull/79 https://github.com/7rulnik/source-map-js/commit/cf7658058ceeaa8619d5ae0ec90be6905209d016 https://github.com/7rulnik/source-map-js/releases/tag/v1.2.2 https://github.com/advisories/GHSA-68fv-2mgg-jv7q

<task_instructions>Resolve this alert by updating the affected package to a non-vulnerable version. Prefer the lowest non-vulnerable version (see the patched_version field above) over the latest to minimize breaking changes. Include a Reachability Assessment section in the PR description. Review the alert_description field to understand which APIs, features, or configurations are affected, then search the codebase for usage of those specific items. If the vulnerable code path is reachable, explain how (which files, APIs, or call sites use the affected functionality) and note that the codebase is actively exposed to this vulnerability. If the vulnerable code path is not reachable, explain why (e.g. the affected API is never called, the vulnerable configuration is not used) and note that the update is primarily to satisfy vulnerability scanners rather than to address an active risk. If the advisory is too vague to determine reachability (e.g. 'improper input validation' with no specific API named), state that reachability could not be determined and explain why. Include a confidence level in the reachability assessment (e.g. high confidence if the advisory names a specific API and you confirmed it is or is not called, low confidence if the usage is indirect and hard to trace). If no patched version is available, check the alert_description field for a Workarounds section — the advisory may describe configuration changes or usage patterns that mitigate the vulnerability without a version update. If a workaround is available, apply it and leave a code comment referencing the advisory identifier explaining it is a temporary mitigation. If neither a patch nor a workaround is available, explain in the PR description why the alert cannot be resolved automatically so a human reviewer can take over. Inspect the repository to determine which package manager is used (e.g. lock files, config files, build scripts) and use that tooling to perform the update — do not edit lock files directly. If the version constraint in the manifest (e.g. package.json, Gemfile, pyproject.toml) caps the version below the fix, update the constraint first. For transitive dependencies, determine whether it is simpler to update the direct dependency that pulls in the vulnerable package or to update the transitive dependency directly, and choose the least disruptive approach. If upgrading to fix the vulnerability forces a major version bump or known breaking changes, review the changelog or release notes, then audit the codebase for usage of affected APIs and fix any breaking changes that are found. If the package manager fails to resolve dependencies (e.g. peer dependency conflicts, incompatible engine constraints), document the error in the PR description rather than attempting increasingly complex workarounds. After updating, check the lock file to confirm the package no longer resolves to a version in the vulnerable range. Keep changes minimal and tightly scoped. Ensure tests, build, type checking, and linting all pass after your changes. If there are any test, lint, or typechecking failures, investigate whether they are caused by the update and fix them if so — do not leave broken tests in the PR. If they were already present before the update, note them in the PR description so a human reviewer can assess whether they are related.</task_instructions>

Co-authored-by: realjkg <24964993+realjkg@users.noreply.github.com>
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bede 576cb33 Oct 08 2026, 11:46 AM

Copilot AI changed the title [WIP] Fix source-map-js vulnerability causing event-loop denial of service Update source-map-js to patched release Oct 8, 2026
Copilot AI requested a review from realjkg October 8, 2026 11:49
@realjkg
realjkg marked this pull request as ready for review October 8, 2026 23:28
@realjkg
realjkg merged commit b96f767 into main Oct 8, 2026
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