CVE-2026-25641

Critical

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.29, there is a sandbox escape vulnerability due to a mismatch between the key on which the validation is performed and the key used for accessing properties. Even though the key used in property accesses is annotated as string, this is never enforced. So, attackers can pass malicious objects that coerce to different string values when used, e.g., one for the time the key is sanitized using hasOwnProperty(key) and a different one for when the key is used for the actual property access. This vulnerability is fixed in 0.8.29.

SeverityCritical
CVSS10.0
Exploit probability—
ProductNyariv Sandboxjs
PublishedFeb 6, 2026
First seenFeb 6, 2026
Weakness typeCWE-367CWE-367

How to fix

Update
  • nyariv sandboxjs0.8.29 or later
  • @nyariv/sandboxjs0.8.29 or later

Affected products

ProductAffected versionsFixed in
nyariv sandboxjsv < 0.8.290.8.29
@nyariv/sandboxjsnpmv < 0.8.290.8.29

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