CVE-2026-25881 @nyariv/sandboxjs has host prototype pollution from sandbox via array intermediary (sandbox escape)
Sandboxed code can escape isolation and execute arbitrary commands on the host by polluting built-in prototypes via array intermediaries.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-25881?
CVE-2026-25881 is a critical code injection vulnerability in nyariv SandboxJS, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
SandboxJS is a JavaScript sandboxing library. Prior to 0.8.31, a sandbox escape vulnerability allows sandboxed code to mutate host built-in prototypes by laundering the isGlobal protection flag through array literal intermediaries. When a global prototype reference (e.g., Map.prototype, Set.prototype) is placed into an array and retrieved, the isGlobal taint is stripped, permitting direct prototype mutation from within the sandbox. This results in persistent host-side prototype pollution and may enable RCE in applications that use polluted properties in sensitive sinks (example gadget: execSync(obj.cmd)). This vulnerability is fixed in 0.8.31.
Weakness: CWE-1321
Which versions are affected by CVE-2026-25881?
2 open source packages ship an affected version, including @nyariv/sandboxjs. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
@nyariv/sandboxjs npm | All versions | 0.8.31 |
@nyariv/sandboxjs npm | All versions | 0.8.31 |
Products include Nyariv Sandboxjs.
How do I fix CVE-2026-25881?
Upgrade @nyariv/sandboxjs to 0.8.31 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-25881 being exploited?
There is no known exploitation of CVE-2026-25881 in the wild and no public exploit code.
Other vulnerabilities in nyariv SandboxJS
- CVE-2026-43898 SandboxJS: Sandbox escape via Function.caller leakage of internal call op
- CVE-2026-34208 SandboxJS: Sandbox integrity escape
- CVE-2026-26954 SandboxJS has a Sandbox Escape
- CVE-2026-25520 SandboxJS has a Sandbox Escape
- CVE-2026-25586 SandboxJS has a Sandbox Escape via Prototype Whitelist Bypass and Host Prototype Pollution
Sources
Also known as GHSA-ww7g-4gwx-m7wj.