fix(coding-agent): bound browser version probes

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Hardened Linux Chromium executable detection to reject non-executable files, non-browser wrappers, and candidates that hang during the version probe.
+
 ## [17.2.9] - 2026-08-05
 
 ### Breaking Changes

packages/coding-agent/src/tools/browser/launch.ts

@@ -205,11 +205,19 @@ function isExecutableFile(p: string): boolean {
 async function isChromiumExecutable(p: string): Promise<boolean> {
 	if (!isExecutableFile(p)) return false;
 	try {
+		const probeTimeoutMs = 3000;
 		const proc = Bun.spawn([p, "--version"], {
 			stdout: "pipe",
 			stderr: "ignore",
+			signal: AbortSignal.timeout(probeTimeoutMs),
+			killSignal: "SIGKILL",
 		});
-		const stdout = await new Response(proc.stdout).text();
+		const stdout = await Promise.race([
+			new Response(proc.stdout).text(),
+			proc.exited.then(() => null),
+			Bun.sleep(probeTimeoutMs).then(() => null),
+		]);
+		if (stdout === null) return false;
 		await proc.exited;
 		return proc.exitCode === 0 && /Chrom|Edg/i.test(stdout);
 	} catch {

packages/coding-agent/test/tools/browser-launch.test.ts

@@ -106,19 +106,38 @@ describe("browser executable selection", () => {
 			try {
 				const wrapper = path.join(tempDir.path(), "google-chrome");
 				const chromium = path.join(tempDir.path(), "chromium");
+				const nonExecutable = path.join(tempDir.path(), "not-executable");
 				await Bun.write(wrapper, "#!/bin/sh\necho browser bridge\n");
 				await Bun.write(chromium, "#!/bin/sh\necho Chromium 123.0\n");
+				await Bun.write(nonExecutable, "#!/bin/sh\necho Chromium 123.0\n");
 				fs.chmodSync(wrapper, 0o755);
 				fs.chmodSync(chromium, 0o755);
+				fs.chmodSync(nonExecutable, 0o644);
 
 				await expect(chromiumExecutableProbeForTest(wrapper)).resolves.toBe(false);
 				await expect(chromiumExecutableProbeForTest(chromium)).resolves.toBe(true);
+				await expect(chromiumExecutableProbeForTest(nonExecutable)).resolves.toBe(false);
 			} finally {
 				await tempDir.remove();
 			}
 		},
 	);
 
+	it.skipIf(process.platform === "win32")("rejects wrappers that hang during the version probe", async () => {
+		const tempDir = TempDir.createSync("@browser-probe-hanging-");
+		try {
+			const hangingWrapper = path.join(tempDir.path(), "google-chrome");
+			await Bun.write(hangingWrapper, "#!/bin/sh\nsleep 60\n");
+			fs.chmodSync(hangingWrapper, 0o755);
+
+			const startedAt = performance.now();
+			await expect(chromiumExecutableProbeForTest(hangingWrapper)).resolves.toBe(false);
+			expect(performance.now() - startedAt).toBeLessThan(5000);
+		} finally {
+			await tempDir.remove();
+		}
+	});
+
 	it("honors PUPPETEER_EXECUTABLE_PATH before a detected Windows system Chrome", async () => {
 		const tempDir = TempDir.createSync("@browser-executable-");
 		try {