fix: reject path traversal sequences in extras validator - #482
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The extras validator was a no-op and accepted any value. Reject values containing parent directory references (..), backslashes, encoded slashes (%2F) or backslashes (%5C), and protocol-relative prefixes (//), including multi-level percent-encoded variants.
wkillerud
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## [5.2.1](v5.2.0...v5.2.1) (2026-08-21) ### Bug Fixes * reject path traversal sequences in extras validator ([#482](#482)) ([310dcbf](310dcbf))
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The extras validator was a no-op. This PR rejects values that contain path traversal sequences or encoded characters that could be used to escape the expected package path.
What is rejected
../../etc/passwd..%2F..%2Fetc%2Fpasswd..%252F..%252F%255Cexternal.example..\external.example,..%5Cexternal.example//external.exampleWhat remains allowed
Normal asset path extras are unaffected:
dist/style.cssmain/index.js/foo/a9-8_3/index.jsCSS and JS files that use relative references (e.g.
url('../fonts/font.woff2')) are also unaffected. The browser resolves..client-side before making the HTTP request, and the WHATWG URL parser in the service normalises any remaining literal..segments before extras are extracted. Encoded traversal sequences cannot be normalised this way and are what this validator now blocks.Tests
Tests are added that fail before the fix and pass after.