fix(enrichment): harden install-script package rendering

review-enrichment/src/analyzers/install-scripts.ts

@@ -7,6 +7,14 @@ import type { EnrichRequest, InstallScriptFinding } from "../types.js";
 import { extractDependencyChanges } from "./dependency-scan.js";
 
 const INSTALL_HOOKS = ["preinstall", "install", "postinstall"];
+const NPM_PACKAGE_RE =
+  /^(?:@[a-z0-9][a-z0-9._-]*\/[a-z0-9][a-z0-9._-]*|[a-z0-9][a-z0-9._-]*)$/;
+const SEMVER_RE =
+  /^(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)(?:-[0-9A-Za-z.-]+)?(?:\+[0-9A-Za-z.-]+)?$/;
+
+function isSafeNpmChange(name: string, version: string): boolean {
+  return NPM_PACKAGE_RE.test(name) && SEMVER_RE.test(version);
+}
 
 /** Analyzer entrypoint: changed npm deps → registry packument → only the versions that run install scripts. */
 export async function scanInstallScripts(
@@ -15,10 +23,13 @@ export async function scanInstallScripts(
 ): Promise<InstallScriptFinding[]> {
   const findings: InstallScriptFinding[] = [];
   for (const change of extractDependencyChanges(req.files ?? [])) {
-    if (change.ecosystem !== "npm") continue;
-    // Scoped packages (@scope/name) encode only the slash in the registry path; the @ stays literal.
+    if (
+      change.ecosystem !== "npm" ||
+      !isSafeNpmChange(change.package, change.to)
+    )
+      continue;
     const response = await fetchImpl(
-      `https://registry.npmjs.org/${change.package.replace("/", "%2F")}`,
+      `https://registry.npmjs.org/${encodeURIComponent(change.package)}`,
     );
     if (!response.ok) continue;
     const data = (await response.json()) as {

review-enrichment/src/render.ts

@@ -10,6 +10,14 @@ const SEVERITY_RANK: Record<string, number> = {
   unknown: 4,
 };
 
+function promptText(value: string): string {
+  return value
+    .replace(/[\u0000-\u001f\u007f]/g, " ")
+    .replace(/\\/g, "\\\\")
+    .replace(/`/g, "\\`")
+    .replace(/([*_{}[\]()#+.!|-])/g, "\\$1");
+}
+
 /** Build the `promptSection` (verbatim splice) + a one-line `systemSuffix` from the findings. Empty when nothing found. */
 export function renderBrief(
   findings: BriefFindings,
@@ -67,7 +75,7 @@ export function renderBrief(
         ? ` (published ${dep.publishedAt.slice(0, 10)})`
         : "";
       lines.push(
-        `- \`${dep.package}@${dep.version}\` runs ${dep.hooks.join("/")} on install${when}`,
+        `- \`${promptText(dep.package)}@${promptText(dep.version)}\` runs ${promptText(dep.hooks.join("/"))} on install${when}`,
       );
     }
   }

review-enrichment/test/enrichment.test.ts

@@ -402,6 +402,56 @@ test("scanInstallScripts: flags npm deps with install hooks, skips clean + non-n
   assert.equal(fail.length, 0);
 });
 
+test("scanInstallScripts: validates npm names and encodes the full registry path", async () => {
+  const calls: string[] = [];
+  const fetchImpl = async (url) => {
+    calls.push(String(url));
+    return {
+      ok: true,
+      json: async () => ({
+        versions: { "1.0.0": { scripts: { install: "x" } } },
+      }),
+    };
+  };
+  const findings = await scanInstallScripts(
+    {
+      repoFullName: "o/r",
+      prNumber: 1,
+      files: [
+        {
+          path: "package.json",
+          patch: [
+            '+    "@scope/pkg": "1.0.0",',
+            '+    "core-js#` **inject** `": "1.0.0",',
+            '+    "bad-version": "1.0.0 || 2.0.0",',
+          ].join("\n"),
+        },
+      ],
+    },
+    fetchImpl,
+  );
+  assert.deepEqual(calls, ["https://registry.npmjs.org/%40scope%2Fpkg"]);
+  assert.equal(findings.length, 1);
+  assert.equal(findings[0].package, "@scope/pkg");
+});
+
+test("renderBrief: escapes install-script markdown and control characters", () => {
+  const r = renderBrief({
+    installScript: [
+      {
+        package: "core-js` **inject**\nnext",
+        version: "1.0.0",
+        hooks: ["postinstall"],
+        publishedAt: null,
+      },
+    ],
+  });
+  assert.ok(
+    r.promptSection.includes("core\\-js\\` \\*\\*inject\\*\\* next@1\\.0\\.0"),
+  );
+  assert.doesNotMatch(r.promptSection, /core-js` \*\*inject\*\*/);
+});
+
 test("renderBrief: renders the install-script block", () => {
   const r = renderBrief({
     installScript: [
@@ -416,7 +466,7 @@ test("renderBrief: renders the install-script block", () => {
   assert.match(r.promptSection, /install scripts \(supply-chain risk/);
   assert.match(
     r.promptSection,
-    /`evil@1.0.0` runs preinstall\/postinstall on install \(published 2026-06-01\)/,
+    /`evil@1\\.0\\.0` runs preinstall\/postinstall on install \(published 2026-06-01\)/,
   );
 });