VulnerabilityModified

CVE-2026-43898

Prior to 0.9.6, sandbox-defined functions expose Function.caller, allowing sandboxed code to recover the internal LispType.Call runtime callback.

CRITICAL 10.0EPSS 0.47%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.47%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1: 10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS: 0.47% probability · 40th percentile
CISA KEV: Not listed
Weakness: CWE-94
Affected: nyariv/sandboxjs
Source: security-advisories@github.com

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

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.