Security Digest · Vulnerability record
CVE-2024-27307: JSONata expression can pollute the "Object" prototype
JSONata is a JSON query and transformation language.
CVSS 9.8 Critical EPSS 1.4% · p73
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.4%, percentile 73: FIRST’s model estimates a 1.4% chance of exploitation activity in the next 30 days, higher than 73% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
jsonata(npm) >= 1.4.0, < 1.8.7, fixed in 1.8.7;jsonata(npm) >= 2.0.0, < 2.0.4, fixed in 2.0.4. Check your lockfile, including transitive dependencies.
What it is
JSONata is a JSON query and transformation language. Starting in version 1.4.0 and prior to version 1.8.7 and 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. 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. As a workaround, one may apply the patch manually.
From the GitHub advisory
Impact
In JSONata versions >= 1.4.0, = 2.0.0,
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.
References
Weakness type: CWE-1321.
Product: jsonata (npm) · Assigned by: GitHub_M · Published: 2024-03-06
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | jsonata | >= 1.4.0, < 1.8.7 | 1.8.7 |
| npm | jsonata | >= 2.0.0, < 2.0.4 | 2.0.4 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| jsonata-js | jsonata | >= 1.4.0, < 1.8.7, >= 2.0.0, < 2.0.4 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 1.42% probability of exploitation activity in the next 30 days; percentile 73.
Timeline
- — GitHub-reviewed advisory GHSA-fqg8-vfv7-8fj8 published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-fqg8-vfv7-8fj8 github.com
- CVE.org record CVE-2024-27307 cve.org
- NVD entry CVE-2024-27307 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com