# JSONata vulnerable to Arbitrary Code Execution via crafted JSONata expressions

Advisory record · `GHSA-2943-5xfg-gq5f`

- **Identifiers:** `GHSA-2943-5xfg-gq5f` · `CVE-2026-77414`
- **State:** Confirmed
- **Severity:** CVSS 9.3 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-94](https://cwe.mitre.org/data/definitions/94.html)
- **Tags:** [Code injection](https://agentprime.io/advisories/tag/code-injection.md)
- **Published:** 21 Aug 2026
- **Updated:** 21 Aug 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 21 Aug 2026, 20:58 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.3: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `jsonata` (npm): affected `>=2.0.0, <2.2.1 || <1.8.8`; fixed in `2.2.1`, `1.8.8`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 9.3 Critical, CVSS 4.0: `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`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0057, the 47th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 21 Aug 2026. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-2943-5xfg-gq5f](https://github.com/advisories/GHSA-2943-5xfg-gq5f)
- [OSV: GHSA-2943-5xfg-gq5f](https://osv.dev/vulnerability/GHSA-2943-5xfg-gq5f)
- <https://github.com/jsonata-js/jsonata/security/advisories/GHSA-2943-5xfg-gq5f>
- <https://github.com/jsonata-js/jsonata/pull/799>
- <https://github.com/jsonata-js/jsonata/commit/59e25144fc3b7125f6befd71b8a6e14e1fa610d2>
- <https://github.com/jsonata-js/jsonata/commit/c41ef185136a7b96ca1049c7745a7503b82193de>
- <https://github.com/jsonata-js/jsonata/commit/f09df8416eab8ff44926fc6527c80fb8701de159>
- <https://github.com/jsonata-js/jsonata>
- <https://github.com/jsonata-js/jsonata/releases/tag/v1.8.8>
- <https://github.com/jsonata-js/jsonata/releases/tag/v2.2.1>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-2943-5xfg-gq5f>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-2943-5xfg-gq5f/>. Everything for agents: <https://agentprime.io/llms.txt>.