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Fencer Vulns
critical 9.3

CVE-2026-77415 json

JSONata: Arbitrary Code Execution via crafted JSONata expressions

published 2026-08-21 2 mo ago modified 2026-10-12 28 d ago also EUVD-2026-64166 , GHSA-66mm-25pp-rfff

cvss
9.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits
0
none known

Summary

JSONata is a JSON query and transformation language. Prior to 1.8.8 and 2.2.1, crafted JSONata expressions could chain several object-integrity weaknesses to execute arbitrary code. The chain could overwrite $clone to mutate objects through evaluateTransformExpression, expose and deconstruct JSONata functions or lambdas through $merge.*, replace proc.arguments.forEach used by applyProcedure, and forge internal lambda state. These primitives allowed an attacker to reach prototype getters, prototype and constructor access, and process.getBuiltinModule with child_process, executing code with the privileges of the host process. This issue is fixed in versions 1.8.8 and 2.2.1.

Patch / fix

  • npm jsonata 1.8.8, 2.2.1
  • jsonata jsonata 1.8.8, 2.2.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-77415 updated cvss 9.8

jsonata: JSONata: Arbitrary Code Execution via crafted JSONata expressions

  • Red Hat Developer Hub 1.10 rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-form-widgets 1791250794
    fixed: vendor fix RHSA-2026:76788
  • Red Hat OpenShift Serverless openshift-serverless-1/kn-eventing-integrations-log-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-s3-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sns-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sqs-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-timer-source-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-s3-source-rhel9, +3 more Red Hat Developer Hub 1.10 rhdh/red-hat-developer-hub-backstage-plugin-lightspeed 1791242743, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator 1791250003, rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend 1791242697, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend 1791251282, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend-module-loki 1791250355, rhdh/red-hat-developer-hub-backstage-plugin-scaffolder-backend-module-orchestrator 1791249640
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.89% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/jsonata-js/jsonata/security/advisories/GHSA-66mm-25pp-rfff referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
npm jsonata
>=2.0.0, <2.2.1
<1.8.8
2.2.1
1.8.8

Affected products

  • jsonata-js jsonata

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.