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fix: reject numeric character references with trailing non-digit characters #45

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Merged
rgrove merged 1 commit into from
Jul 11, 2026
Merged

fix: reject numeric character references with trailing non-digit characters #45

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3 changes: 2 additions & 1 deletion src/lib/Parser.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -609,7 +609,8 @@ export class Parser {
? parseInt(ref.slice(2), 16) // Hex codepoint.
: parseInt(ref.slice(1), 10); // Decimal codepoint.

if (isNaN(codePoint)) {
if (isNaN(codePoint)
|| !/^#(?:x[0-9A-Fa-f]+|[0-9]+)$/.test(ref)) {
throw this.error('Invalid character reference');
}

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11 changes: 11 additions & 0 deletions tests/lib/Parser.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -408,6 +408,17 @@ describe('Parser', () => {
assert.strictEqual(parseXml('<a>&#xD;&#xA;</a>').root.children[0].text, '\r\n');
});

// A numeric character reference must consist solely of digits, so a
// reference like `&#65a;` or `&#x41g;` is malformed and must be rejected
// rather than silently truncated to the leading numeric portion.
// https://www.w3.org/TR/2008/REC-xml-20081126/#NT-CharRef
it('rejects a numeric character reference with trailing non-digit characters', () => {
assert.throws(() => parseXml('<a>&#65a;</a>'), /Invalid character reference/);
assert.throws(() => parseXml('<a>&#48f;</a>'), /Invalid character reference/);
assert.throws(() => parseXml('<a>&#x41g;</a>'), /Invalid character reference/);
assert.throws(() => parseXml('<a b="&#65z;" />'), /Invalid character reference/);
});

it('handles many character references in a single attribute', () => {
let { root } = parseXml('<a b="&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;"/>');
assert.strictEqual(root.attributes.b, "<".repeat(35));
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