CVE-2026-12208 is a medium-severity (CVSS 5.3) Code Injection vulnerability in jsonata. A fix is available for jsonata — see the affected versions and patch details below.
jsonata: Function Binding Prototype Pollution via hasOwnProperty Override
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-12208.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-12208 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
jsonatanpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jsonata | all versions | 1.8.8npm install jsonata@1.8.8 |
| 📦npm | jsonata | ≥ 2.0.0&&< 2.2.1 | 2.2.1npm install jsonata@2.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jsonata, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update jsonata to 1.8.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-12208 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat ships the jsonata library as a dependency in several products including OpenShift Serverless, Red Hat JBoss EAP Expansion Pack (XP), Cryostat, and Konflux. The vulnerability allows prototype pollution via the createFrame function, which could be exploited if user-controlled input is passed to jsonata…
Do not pass untrusted or user-controlled input to jsonata expressions. If user input must be evaluated, sanitize it to prevent prototype pollution payloads targeting __proto__ or constructor.prototype.Source: Red Hat security advisory for CVE-2026-12208 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-12208 in your dependencies?
Find it across npm, including transitive dependencies.