fast-uri - npm Package Compare versions

Comparing version 3.1.3 to 3.1.4

index.js

@@ -205,2 +205,6 @@ 'use strict'
 
+// Captures the authority component (between "//" and the next "/", "?" or "#"),
+// with or without a scheme prefix, for the literal-backslash rejection below.
+const AUTHORITY_PREFIX = /^(?:[^#/:?]+:)?\/\/([^/?#]*)/
+
 /**
@@ -252,2 +256,15 @@ * @param {import('./types/index').URIComponent} parsed
 
+  // A literal backslash (U+005C) is not a valid RFC 3986 URI character and is
+  // not an authority delimiter. Reject it in the authority rather than
+  // rewriting it: normalizing "\" -> "/" (WHATWG error recovery) could silently
+  // change the resource identified by an otherwise-invalid input, and lets "\"
+  // act as a host delimiter here while Node's native URL parses a different
+  // host (SSRF / redirect / origin-allowlist bypass). Percent-encoded %5C is
+  // untouched and remains valid encoded data.
+  const authorityMatch = uri.match(AUTHORITY_PREFIX)
+  if (authorityMatch !== null && authorityMatch[1].indexOf('\\') !== -1) {
+    parsed.error = 'URI authority must not contain a literal backslash.'
+    malformedAuthorityOrPort = true
+  }
+
   const matches = uri.match(URI_PARSE)
@@ -254,0 +271,0 @@

package.json

 {
   "name": "fast-uri",
   "description": "Dependency-free RFC 3986 URI toolbox",
-  "version": "3.1.3",
+  "version": "3.1.4",
   "main": "index.js",
@@ -6,0 +6,0 @@ "type": "commonjs",

test/security.test.js

@@ -162,1 +162,63 @@ 'use strict'
 })
+
+test('parse rejects a literal backslash in the authority as malformed (RFC 3986)', (t) => {
+  // Regression for the host-confusion bypass: a literal "\" is invalid RFC 3986
+  // syntax and must be flagged malformed, not silently rewritten. Otherwise "\"
+  // acts as a host delimiter here while Node's native URL parses a different
+  // host, defeating a host-based SSRF/redirect/origin allowlist.
+  const cases = [
+    'http://evil.com\\@allowed.com',
+    'https://169.254.169.254\\@trusted.example.com',
+    'http://127.0.0.1\\@public.example.com',
+    'https://attacker.com\\@api.internal',
+    'http://a\\@b',
+    'ws://evil.com\\@allowed.com/chat',
+    'wss://evil.com\\@allowed.com/chat',
+    'http://evil.com\\%40allowed.com',
+    '//evil.com\\@allowed.com'
+  ]
+
+  t.plan(cases.length)
+
+  cases.forEach((input) => {
+    t.equal(
+      fastURI.parse(input).error,
+      'URI authority must not contain a literal backslash.',
+      input
+    )
+  })
+})
+
+test('normalize does not canonicalize a literal-backslash URI into a different valid URL', (t) => {
+  const cases = [
+    'http://evil.com\\@allowed.com',
+    'https://attacker.com\\@api.internal'
+  ]
+
+  t.plan(cases.length)
+
+  cases.forEach((input) => {
+    t.equal(fastURI.normalize(input), input, input)
+  })
+})
+
+test('parse leaves percent-encoded %5C untouched as encoded data (not rejected)', (t) => {
+  // Only the literal "\" byte is rejected; %5C stays valid encoded data and
+  // does not diverge from the native URL parser, so it must not be flagged.
+  const input = 'http://[e-mail]'
+  const parsed = fastURI.parse(input)
+
+  t.plan(2)
+  t.notOk(parsed.error, '%5C is valid encoded data, not malformed')
+  t.equal(parsed.host, new URL(input).hostname, '%5C host matches native URL (no divergence)')
+})
+
+test('parse does not reject a literal backslash in the query or fragment', (t) => {
+  // The rejection is scoped to the authority/path (the host-confusion surface);
+  // a backslash after "?"/"#" is normalized as encoded data as before.
+  const parsed = fastURI.parse('http://host.example.com/?x=\\y#z\\w')
+
+  t.plan(2)
+  t.notOk(parsed.error, 'backslash in query/fragment does not mark the URI malformed')
+  t.equal(parsed.host, 'host.example.com', 'host parsed normally')
+})

New alerts

URL strings

Supply chain risk

Package contains fragments of external URLs or IP addresses, which the package may be accessing at runtime.

Fixed alerts

URL strings

Supply chain risk

Package contains fragments of external URLs or IP addresses, which the package may be accessing at runtime.

Improved metrics

Total package byte prevSize

160945

2.05%

Lines of code

3739

1.82%

No dependency changes