Impact The V8 inspector intentionally allows arbitrary code execution within the Workers sandbox for debugging. wrangler dev would previously start an inspector server listening on all network interfaces. This would allow an attacker on the local network to connect to the inspector and run arbitrary code. Additionally, the inspector server did not validate Origin/Host headers, granting an attacker that can trick any user on the local network into opening a malicious website the ability to run code. If wrangler dev --remote was being used, an attacker could access production resources if they were bound to the worker.
Patches This issue was fixed in wrangler@3.19.0 and wrangler@2.20.2. Whilst wrangler dev's inspector server listens on local interfaces by default as of wrangler@3.16.0, an SSRF vulnerability in miniflare allowed access from the local network until wrangler@3.18.0. wrangler@3.19.0 and wrangler@2.20.2 introduced validation for the Origin/Host headers.
Workarounds Unfortunately, Wrangler doesn't provide any configuration for which host that inspector server should listen on. Please upgrade to at least wrangler@3.16.0, and configure Wrangler to listen on local interfaces instead with wrangler dev --ip 127.0.0.1 to prevent SSRF. This removes the local network as an attack vector, but does not prevent an attack from visiting a malicious website.
References - https://github.com/cloudflare/workers-sdk/issues/4430 - https://github.com/cloudflare/workers-sdk/pull/4437 - https://github.com/cloudflare/workers-sdk/pull/4535 - https://github.com/cloudflare/workers-sdk/pull/4550
Impact Sending specially crafted HTTP requests and inspector messages to Wrangler's dev server could result in any file on the user's computer being accessible over the local network. An attacker that could trick any user on the local network into opening a malicious website could also read any file.
Patches This issue was fixed in wrangler@3.19.0. Wrangler will now only serve files that are part of your bundle, or referenced by your bundle's source maps.
Workarounds Configure Wrangler to listen on local interfaces instead with wrangler dev --ip 127.0.0.1. This is the default as of wrangler@3.16.0, and removes the local network as an attack vector, but does not prevent an attack from visiting a malicious website.
References - https://github.com/cloudflare/workers-sdk/pull/4532 - https://github.com/cloudflare/workers-sdk/pull/4535
Impact The Wrangler command line tool (<=wrangler@3.1.0 or <=wrangler@2.20.1) was affected by a directory traversal vulnerability when running a local development server for Pages (wrangler pages dev command). This vulnerability enabled an attacker in the same network as the victim to connect to the local development server and access the victim's files present outside of the directory for the development server.
Patches Wrangler2: Upgrade to v2.20.1 or higher. Wrangler3: Upgrade to v3.1.1 or higher.
References Workers SDK on Github Wrangler docs CVE-2023-3348