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CVE Record

CVE-2026-77415: JSONata: Arbitrary Code Execution via crafted JSONata expressions

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.

CriticalCVSS 9.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

Applications that let attackers supply JSONata expressions may allow them to run code with the application's operating-system privileges. Successful exploitation could expose data, alter systems, or disrupt service. JSONata versions before 1.8.8 and versions 2.0.0 through 2.2.0 are affected.

Executive priority

Treat as an immediate remediation priority wherever untrusted expressions reach affected JSONata versions. Rapidly inventory internet-facing and multi-tenant services, upgrade exposed systems first, and apply temporary input restrictions if deployment cannot occur promptly. Do not claim compromise solely from version presence.

Technical view

Crafted expressions chain object-integrity weaknesses affecting transforms, function merging, procedure application, and forged lambda state. The chain reaches prototype and constructor access, then Node.js built-in modules capable of launching child processes. Fixed releases harden the affected mechanisms in JSONata 1.8.8 and 2.2.1.

Likely exposure

Exposure is highest where a network-accessible application evaluates JSONata expressions controlled by unauthenticated or untrusted users. Applications using affected versions only with fixed, trusted expressions have lower practical exposure, but should still upgrade. Both direct and transitive dependencies require review.

Exploitation context

The supplied CVSS 4.0 score is 9.3, reflecting network exploitation with low complexity, no privileges, and no user interaction. The source bundle reports that this CVE is not in KEV and provides no evidence of active exploitation. Public technical details may nevertheless increase future exploitation risk.

Researcher notes

CWE-94 applies. The vulnerability is a multi-stage integrity-bypass chain rather than a single unsafe call. Validate exposure by tracing expression provenance and evaluation boundaries. The supplied evidence establishes code-execution capability and fixed versions, but does not establish exploitation in the wild or enumerate every embedding product.

Mitigation direction

  • Upgrade JSONata 1.x deployments to version 1.8.8 or later.
  • Upgrade JSONata 2.x deployments to version 2.2.1 or later.
  • Until upgraded, prevent untrusted users from supplying or modifying JSONata expressions.
  • Run affected services with minimal operating-system permissions and restrict unnecessary process capabilities.
  • Review vendor advisory and release notes for deployment-specific guidance.

Validation and detection

  • Inventory direct and transitive JSONata versions across production, development, and build environments.
  • Identify every route, workflow, or integration that evaluates user-influenced JSONata expressions.
  • Confirm deployed runtime versions, not only lockfiles, are 1.8.8 or 2.2.1 and later.
  • Regression-test legitimate expressions after upgrading, especially transforms, merged objects, functions, and lambdas.
  • Review logs for unexpected child processes or suspicious expression-evaluation failures.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-94: Code execution behavior lookup

Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2026-77415 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.3 (4.0)
Known Exploited
No
Published

Vector: 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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
1ADP providers
12Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: yesTechnical Impact: total

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.3CVSS 4.0CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——GitHub_M

Vulnerability scoring details

Base CVSS 4.0 score

9.3Critical
CVSS 4.0 vector shape for CVE-2026-77415Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: 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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
jsonata-jsjsonata< 1.8.8, >= 2.0.0, < 2.2.1Listed
Weakness

CWE details

CWE-94

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-94 · source CWE mapping

Improper Control of Generation of Code

Improper Control of Generation of Code represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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