# CVE-2026-77414: JSONata arbitrary code execution via expression injection

Source: https://junglewise.ai/threats/cve-2026-77414-jsonata-arbitrary-code-execution-in-expression-evaluation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-21. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-77414 · Severity: critical · CVSS 4 · Published 2026-08-21

JSONata is a popular JavaScript library used to query and transform JSON data. A critical flaw in versions before 2.2.1 and 1.8.8 allows attackers to execute arbitrary code by crafting malicious JSONata expressions that bypass security restrictions. This could allow an attacker to compromise any application that processes untrusted JSONata expressions, leading to unauthorized access to sensitive data, system commands execution, or complete server compromise.

Technologies: [JSONata](https://junglewise.ai/threats/technologies/jsonata). Vendors: [JSONata](https://junglewise.ai/threats/vendors/jsonata).

## Quick answers

**Is CVE-2026-77414 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77414 being exploited in the wild.

**How severe is CVE-2026-77414?** Critical severity, with a CVSS score of 4, published 21 August 2026.

**Which products and versions are affected?** JSONata All versions before 1.8.8; versions 2.0.0 through 2.2.0.

**Is there a fix for CVE-2026-77414?** A patch was published on 2026-07-13: Patched in JSONata 2.2.1 and 1.8.8 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-77414 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-77414?** Check whether you run JSONata at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the environment.lookup function's bypassable hasOwnProperty check (CVE-2026-77414, CWE-94: Code Injection). An attacker can craft expressions using prototype pollution techniques—reassigning $hasOwnProperty, $__proto__, and $constructor variables to circumvent security protections—and then execute arbitrary Node.js code via the constructor function. The attack requires no authentication and can be triggered by evaluating any untrusted JSONata expression. The vulnerability was patched in JSONata 2.2.1 and backported to 1.8.8 in PR #799. A working proof-of-concept demonstrates spawning shell commands via process.getBuiltinModule('child_process').execSync().

## Affected products

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

## Identifiers

- CVE-2026-77414
- GHSA-2943-5xfg-gq5f

## Timeline

- 2026-07-13: disclosed: Advisory published by GitHub
- 2026-07-13: patched: Patched in JSONata 2.2.1 and 1.8.8
- 2026-08-21: advisory: Advisory updated on GitHub

## References

- [https://api.github.com/users/c0rydoras](https://api.github.com/users/c0rydoras)
- [https://github.com/c0rydoras](https://github.com/c0rydoras)
- [https://api.github.com/users/c0rydoras/gists%7B/gist_id%7D](https://api.github.com/users/c0rydoras/gists%7B/gist_id%7D)
- [https://api.github.com/users/c0rydoras/repos](https://api.github.com/users/c0rydoras/repos)
- [https://avatars.githubusercontent.com/u/110528300?v=4](https://avatars.githubusercontent.com/u/110528300?v=4)
- [https://api.github.com/users/c0rydoras/events%7B/privacy%7D](https://api.github.com/users/c0rydoras/events%7B/privacy%7D)

## Related threats

- [JSONata arbitrary code execution via crafted expressions](https://junglewise.ai/threats/cve-2026-77415-jsonata-arbitrary-code-execution-via-crafted-expressions)
- [JSONata arbitrary code execution in lookup function](https://junglewise.ai/threats/cve-2026-77413-jsonata-arbitrary-code-execution-in-lookup-function)
- [jsonata-js JSONata Denial of Service in $toMillis function](https://junglewise.ai/threats/cve-2026-52746-jsonata-js-jsonata-denial-of-service-in-tomillis-function)
- [JSONata prototype pollution in createFrame function](https://junglewise.ai/threats/cve-2026-12208-jsonata-prototype-pollution-in-createframe-function)
- [JSONata prototype pollution via transform operator](https://junglewise.ai/threats/cve-2024-27307-jsonata-prototype-pollution-via-transform-operator)