diff --git a/src/application/javascript/JavaScriptArtifactPathResolution.ts b/src/application/javascript/JavaScriptArtifactPathResolution.ts
index c2485a11d..bb93419d7 100644
--- a/src/application/javascript/JavaScriptArtifactPathResolution.ts
+++ b/src/application/javascript/JavaScriptArtifactPathResolution.ts
@@ -264,6 +264,12 @@ const htmlCandidate = (
     return unresolvedOutcome(input, "external", [
       "The document base href is external, so its script reference is not a local artifact path.",
     ]);
+  // Removing URL tabs and newlines can join an encoded dot or separator that
+  // the raw declaration split, so admit the parsed URL text again.
+  if (!admitsCanonicalPathSyntax(declared))
+    return unresolvedOutcome(input, "rejected", [
+      "Encoded dot or separator bytes are rejected before artifact path resolution.",
+    ]);
   const declaredPath = percentDecodeUrlPath(declared);
   if (declaredPath === null)
     return unresolvedOutcome(input, "rejected", [
diff --git a/src/application/javascript/JavaScriptHtmlBaseResolution.test.ts b/src/application/javascript/JavaScriptHtmlBaseResolution.test.ts
index 49a5f7ad2..681d79099 100644
--- a/src/application/javascript/JavaScriptHtmlBaseResolution.test.ts
+++ b/src/application/javascript/JavaScriptHtmlBaseResolution.test.ts
@@ -150,6 +150,12 @@ describe("HTML reference URL text", () => {
       });
     },
   );
+  it("rejects a base href whose URL whitespace splits an encoded separator", () => {
+    expect(resolve("app.js", "a%2\nf/")).toMatchObject({
+      resolution_status: "rejected",
+      resolved_path: null,
+    });
+  });
   it("rejects a base href that decodes to NUL", () => {
     expect(resolve("app.js", "/a%00/")).toMatchObject({
       resolution_status: "rejected",
@@ -164,7 +170,7 @@ describe("HTML reference URL text", () => {
       });
     },
   );
-  it.each(["%2e%2e/app.js", "a%2fapp.js"])(
+  it.each(["%2e%2e/app.js", "a%2fapp.js", "%2\nfapp.js", "%2\ne%2\te/app.js"])(
     "still rejects encoded dot and separator bytes in %j",
     (declared) => {
       expect(resolve(declared, "")).toMatchObject({