CVE-2026-43898Public exploitNetwork attack vector

Sandbox escape via exposed Function.caller callback

Published May 28, 2026 · Updated May 28, 2026

Code injection in nyariv SandboxJS before 0.9.6 allows attackers to execute arbitrary host JavaScript via sandboxed code. The prop.ts property-access operation permits caller, callee, and arguments on sandbox-created functions, exposing the privileged LispType.Call callback, which trusts forged operand fields. Exploitation requires the host application to run attacker-controlled sandbox code; success grants the code the host process's JavaScript privileges.

CVSS severity10.0
Critical
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in nyariv SandboxJS before 0.9.6 allows attackers to execute arbitrary host JavaScript via sandboxed code. The prop.ts property-access operation permits caller, callee, and arguments on sandbox-created functions, exposing the privileged LispType.Call callback, which trusts forged operand fields. Exploitation requires the host application to run attacker-controlled sandbox code; success grants the code the host process's JavaScript privileges.

The record

CVE
CVE-2026-43898
Published
May 28, 2026
Updated
May 28, 2026
Vendor
nyariv
Product
SandboxJS
Classifications
CWE-94, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 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.

  1. Affected versionversion=< 0.9.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

nyariv · SandboxJSversion=< 0.9.6

Published CVSS scores

10.0GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1203Exploitation for Client Execution

Public exploit references

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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