CVE-2026-43898

Name: CVE-2026-43898
Creator: NVD / NIST
Published: 2026-05-28T18:16:32.837+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 10/10EPSS 0.47%

Last modified Jun 17, 2026

CVE-2026-43898 is a critical-severity vulnerability rated 10/10 on the CVSS scale. SandboxJS is a JavaScript sandboxing library. Prior to 0.9.6, sandbox-defined functions expose Function.caller, allowing sandboxed code to recover the internal LispType.Call runtime callback. EPSS estimates a 0.47% chance of exploitation in the next 30 days.

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.9.6, sandbox-defined functions expose Function.caller, allowing sandboxed code to recover the internal LispType.Call runtime callback. That callback can then be invoked with attacker-controlled fake context and obj values to extract blocked host statics, recover the real host Function constructor, and execute arbitrary host JavaScript. This vulnerability is fixed in 0.9.6.

Metrics

CVSS 3.1

10/10

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

EPSS Probability

0.47%

37.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-94

Affected Software

Vendor	Product	Versions
Nyariv	Sandboxjs	< 0.9.6

References

https://github.com/nyariv/SandboxJS/commit/826865251232611ec94078bab5a18ec875dad4a5Patch
https://github.com/nyariv/SandboxJS/security/advisories/GHSA-g8f2-4f4f-5jqwExploit, Vendor Advisory
https://github.com/nyariv/SandboxJS/security/advisories/GHSA-g8f2-4f4f-5jqwExploit, Vendor Advisory

Timeline

Published: May 28, 2026
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2026-43898?

How severe is CVE-2026-43898?

CVE-2026-43898 has a CVSS score of 10/10 (CRITICAL severity). The EPSS model estimates a 0.47% probability of exploitation in the next 30 days.

How do I fix CVE-2026-43898?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-43898?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST