---
title: "CVE-2026-77415: JSONata vulnerable to Arbitrary Code Execution via crafted JSONata expressions"
url: https://erroneo.us/security/cve/CVE-2026-77415/
description: "CVE-2026-77415 (jsonata (npm)): JSONata is a JSON query and transformation language. Prior to 1.8.8 and 2.2.1, crafted JSONata expressions could chain…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-21
date_modified: 2026-08-25
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-77415"
kev: false
cvss: 9.3
epss: 0.00892
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-77415: JSONata vulnerable to Arbitrary Code Execution via crafted JSONata expressions

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.9% , percentile 59: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 59% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes jsonata (npm) >= 2.0.0, < 2.2.1, fixed in 2.2.1 ; jsonata (npm) < 1.8.8, fixed in 1.8.8 . Check your lockfile, including transitive dependencies.

## What it is

JSONata is a JSON query and transformation language. Prior to 1.8.8 and 2.2.1, crafted JSONata expressions could chain several object-integrity weaknesses to execute arbitrary code. The chain could overwrite $clone to mutate objects through evaluateTransformExpression, expose and deconstruct JSONata functions or lambdas through $merge., replace proc.arguments.forEach used by applyProcedure, and forge internal lambda state. These primitives allowed an attacker to reach prototype getters, prototype and constructor access, and process.getBuiltinModule with childprocess, executing code with the privileges of the host process. This issue is fixed in versions 1.8.8 and 2.2.1.

## Affected packages

- npm `jsonata` >= 2.0.0, < 2.2.1 → fixed: 2.2.1
- npm `jsonata` < 1.8.8 → fixed: 1.8.8

## Affected products (CVE record)

- jsonata-js jsonata: < 1.8.8, >= 2.0.0, < 2.2.1

## Severity

- GitHub_M CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.89% probability of exploitation activity in the next 30 days; percentile 59.

## Sources

- [GitHub Advisory GHSA-66mm-25pp-rfff](https://github.com/advisories/GHSA-66mm-25pp-rfff)
- [CVE.org record CVE-2026-77415](https://www.cve.org/CVERecord?id=CVE-2026-77415)
- [NVD entry CVE-2026-77415](https://nvd.nist.gov/vuln/detail/CVE-2026-77415)
- [github.com](https://github.com/jsonata-js/jsonata/security/advisories/GHSA-66mm-25pp-rfff)
- [github.com](https://github.com/jsonata-js/jsonata/pull/799)
- [github.com](https://github.com/jsonata-js/jsonata/pull/800)
- [github.com](https://github.com/jsonata-js/jsonata/pull/802)
- [github.com](https://github.com/jsonata-js/jsonata/commit/47c0e58542202c705726663166dbee5fcae47d06)
- [github.com](https://github.com/jsonata-js/jsonata/commit/4b217d514376e30cba278941298d7ba97c4a6c6e)
- [github.com](https://github.com/jsonata-js/jsonata/commit/59e25144fc3b7125f6befd71b8a6e14e1fa610d2)
- [github.com](https://github.com/jsonata-js/jsonata/commit/f09df8416eab8ff44926fc6527c80fb8701de159)
- [github.com](https://github.com/jsonata-js/jsonata/commit/f174348c7fa30f271b63ddedf0767e814004bc4d)
- [github.com](https://github.com/jsonata-js/jsonata/releases/tag/v1.8.8)
- [github.com](https://github.com/jsonata-js/jsonata/releases/tag/v2.2.1)

---
Source page: https://erroneo.us/security/cve/CVE-2026-77415/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt