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CVE-2026-43898

SandboxJS: Sandbox escape via Function.caller leakage of internal call op

Published: May 28, 2026Updated: May 28, 2026 Sources: CVE List NVD
NVD MITRE
10.0CVSS
CRITICAL

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.

EPSS Score
0.1%
Top 80.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:CC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High

Weaknesses

CWE-94

Affected Products

SandboxJS
nyariv
sandboxjs
nyariv

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://github.com/nyariv/SandboxJS/security/advisories/GHSA-g8f2-4f4f-5jqw
github.com
https://github.com/nyariv/SandboxJS/commit/826865251232611ec94078bab5a18ec875dad4a5
github.com

Timeline

Published
May 28, 2026
Last Updated
May 28, 2026
News mentions
1

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