CVE-2024-27307 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in jsonata. A fix is available for jsonata — see the affected versions and patch details below.
JSONata expression can pollute the "Object" prototype
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-27307.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-27307 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
Impact
In JSONata versions >= 1.4.0, < 1.8.7 and >= 2.0.0, < 2.0.4, a malicious expression can use the transform operator to override properties on the Object constructor and prototype. This may lead to denial of service, remote code execution or other unexpected behavior in applications that evaluate user-provided JSONata expressions.
Patch
This issue has been fixed in JSONata versions >= 1.8.7 and >= 2.0.4. Applications that evaluate user-provided expressions should update ASAP to prevent exploitation. The following patch can be applied if updating is not possible.
--- a/src/jsonata.js
+++ b/src/jsonata.js
@@ -1293,6 +1293,13 @@ var jsonata = (function() {
}
for(var ii = 0; ii < matches.length; ii++) {
var match = matches[ii];
+ if (match && (match.isPrototypeOf(result) || match instanceof Object.constructor)) {
+ throw {
+ code: "D1010",
+ stack: (new Error()).stack,
+ position: expr.position
+ };
+ }
// evaluate the update value for each match
var update = await evaluate(expr.update, match, environment);
// update must be an object
@@ -1539,7 +1546,7 @@ var jsonata = (function() {
if (typeof err.token == 'undefined' && typeof proc.token !== 'undefined') {
err.token = proc.token;
}
- err.position = proc.position;
+ err.position = proc.position || err.position;
}
throw err;
}
@@ -1972,6 +1979,7 @@ var jsonata = (function() {
"T1007": "Attempted to partially apply a non-function. Did you mean ${{{token}}}?",
"T1008": "Attempted to partially apply a non-function",
"D1009": "Multiple key definitions evaluate to same key: {{value}}",
+ "D1010": "Attempted to access the Javascript object prototype", // Javascript specific
"T1010": "The matcher function argument passed to function {{token}} does not return the correct object structure",
"T2001": "The left side of the {{token}} operator must evaluate to a number",
"T2002": "The right side of the {{token}} operator must evaluate to a number",
References
https://github.com/jsonata-js/jsonata/releases/tag/v2.0.4
Credit
Thank you to Albert Pedersen of Cloudflare for disclosing this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jsonata | ≥ 1.4.0&&< 1.8.7 | 1.8.7npm install jsonata@1.8.7 |
| 📦npm | jsonata | ≥ 2.0.0&&< 2.0.4 | 2.0.4npm install jsonata@2.0.4 |
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 1.8.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27307 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-27307 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-27307. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
This issue affects the @roadiehq/scaffolder-backend-module-utils plugin shipped in Red Hat Developer Hub. However, currently, this plugin is in technology preview. For more information, see the link…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Developer Hub 1.2 on RHEL 9 | rhdh/rhdh-hub-rhel9:1.2-105 | RHEA-2024:4071 |
Frequently Asked Questions
Is CVE-2024-27307 in your dependencies?
O3 Security finds CVE-2024-27307 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.