From 400703154ed051fc3880a8256433cd7dbdd5459c Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Mon, 18 May 2026 16:18:00 +0200
Subject: [PATCH] fix: ignore plugin-supplied target in ui.openExternalUrl to
 block host-frame hijack

---
 lib/plugin-sandbox/host-api.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/plugin-sandbox/host-api.ts b/lib/plugin-sandbox/host-api.ts
index b1eb4fc4..29626bb1 100644
--- a/lib/plugin-sandbox/host-api.ts
+++ b/lib/plugin-sandbox/host-api.ts
@@ -296,8 +296,9 @@ export async function dispatchApiCall(
       if (parsed.protocol !== 'http:' && parsed.protocol !== 'https:') {
         throw new Error(`ui.openExternalUrl: ${parsed.protocol} not allowed`);
       }
-      const target = typeof args[1] === 'string' ? (args[1] as string) : '_blank';
-      window.open(parsed.toString(), target, 'noopener,noreferrer');
+      // Always open in a new tab; plugins must not be able to navigate the
+      // host window (_self/_top/_parent) to an attacker-controlled origin.
+      window.open(parsed.toString(), '_blank', 'noopener,noreferrer');
       return undefined;
     }