Which versions of ThingsBoard are affected by CVE-2026-53676?

ThingsBoard versions prior to v4.3.1.2 contain a sandbox escape vulnerability in the JavaScript rule-chain executor that allows authenticated tenant administrators to achieve arbitrary code…

How to fix or mitigate CVE-2026-53676?

Within 24 hours: Inventory all ThingsBoard deployments, document versions, and restrict TENANT_ADMIN role assignment to absolutely necessary personnel. Within 7 days: Implement strict audit logging and monitoring of JavaScript rule-chain modifications; disable JavaScript-based rule-chain execution if operationally feasible. Within 30 days: Monitor vendor security advisories for patch availability; establish upgrade planning timeline.

ThingsBoard CVE-2026-53676

Q: What is the CVSS score of CVE-2026-53676?

CVE-2026-53676 has a CVSS 4.0 base score of 8.6 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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. EPSS exploitation probability: 0.8%.

EUVD-2026-37828 HIGH

Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution) (CWE-1321)

2026-06-17 jpcert

GHSA-prc2-x3qx-38m9

Prototype Pollution RCE Thingsboard

8.6

CVSS 4.0 · Vendor: jpcert

Severity by source

Vendor (jpcert) PRIMARY

8.6 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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

vuln.today AI

7.2 HIGH

Network-reachable API, low complexity, requires TENANT_ADMIN (PR:H), no UI; sandbox escape crosses trust boundary into host js-executor process so S:C with full CIA impact.

3.1 AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

4.0 AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L

Primary rating from Vendor (jpcert).

CVSS VectorVendor: jpcert

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Lifecycle Timeline

Analysis Updated

Jun 18, 2026 - 03:43 vuln.today

v3 (cvss_changed)

Analysis Updated

Jun 18, 2026 - 03:43 vuln.today

v2 (cvss_changed)

Re-analysis Queued

Jun 18, 2026 - 03:38 vuln.today

cvss_changed

CVSS changed

Jun 18, 2026 - 03:38 NVD

7.2 (HIGH) 8.6 (HIGH)

Source Code Evidence Fetched

Jun 17, 2026 - 23:30 vuln.today

Analysis Generated

Jun 17, 2026 - 23:30 vuln.today

DescriptionCVE.org

ThingsBoard contains a prototype pollution vulnerability which may lead to arbitrary code execution within a sandboxed context by a user who can log in to the affected product with the tenant administrator privilege (TENANT_ADMIN).

AnalysisAI

Sandbox escape via prototype pollution in ThingsBoard (versions prior to v4.3.1.2) allows a TENANT_ADMIN-authenticated user to achieve arbitrary code execution within the tb-js-executor sandboxed JavaScript context. The flaw lets a rule-chain script reach the host realm through the args.constructor.constructor chain (e.g., synthesizing a Function that returns process), defeating the intended VM isolation. No public exploit identified at time of analysis, though the upstream regression test in PR #15600 effectively documents the escape technique.

Technical ContextAI

ThingsBoard is an open-source IoT platform whose rule engine lets tenants author JavaScript snippets that are evaluated by the tb-js-executor microservice (Node.js vm.runInNewContext against a sandbox object). CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes - 'Prototype Pollution') applies because user-controlled args reached the script with an accessible prototype chain, exposing args.constructor.constructor and thereby host-realm globals such as process. The fix in PR #15600 hardens the JsExecutor (msa/js-executor/api/jsExecutor.ts) sandbox construction and adds a black-box regression (JsExecutorSandboxIsolationTest) asserting that synthesizing Function('return process')() from within the script throws 'process is not defined'.

RemediationAI

Vendor-released patch: ThingsBoard v4.3.1.2 - upgrade to this version or later, which contains the JsExecutor sandbox hardening from PR https://github.com/thingsboard/thingsboard/pull/15600 and the accompanying regression test. Until the upgrade is applied, restrict TENANT_ADMIN role assignment to trusted operators, rotate tenant-admin credentials, and audit rule chains for suspicious scripts referencing constructor.constructor, process, require, or mainModule; on multi-tenant deployments consider temporarily disabling the rule-chain testScript and script-node functionality for untrusted tenants (this disables legitimate rule-engine JS development workflows). Do not rely on script.use_sandbox=false as a workaround - the patched code now explicitly warns that this mode runs scripts in the host realm with no isolation.