Arbitrary code execution via inherited prototype access
Published Aug 21, 2026 · Updated Aug 21, 2026
Code injection in JSONata allows attackers to execute arbitrary code with host-process privileges via crafted expressions supplied to the evaluator. The src/functions.js lookup function reads input[key] without an Object.prototype.hasOwnProperty check, exposing inherited setters, getters, and constructor members. Reachability requires an application to evaluate attacker-controlled expressions; successful exploitation loads child_process and runs commands as the host process.
Summary
What happened
Code injection in JSONata allows attackers to execute arbitrary code with host-process privileges via crafted expressions supplied to the evaluator. The src/functions.js lookup function reads input[key] without an Object.prototype.hasOwnProperty check, exposing inherited setters, getters, and constructor members. Reachability requires an application to evaluate attacker-controlled expressions; successful exploitation loads child_process and runs commands as the host process.
The record
- CVE
- CVE-2026-77413
- Published
- Aug 21, 2026
- Updated
- Aug 21, 2026
- Vendor
- JSONata
- Product
- JSONata
- Classifications
- CWE-94, T1059.007
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 21, 2026CVE publishedPublication date reported by the CVE source.
- Aug 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.2.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub advisory JSONata crafted-expression PoCproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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