What is CVE-2026-25641?

CVE-2026-25641 is a critical-severity vulnerability in Nyariv Sandboxjs, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 10.0/10. Published 2026-02-06.

How severe is CVE-2026-25641?

Critical severity. CVSS v3 base score is 10.0 out of 10.

Vulnerability in Nyariv Sandboxjs

CVE-2026-25641

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 us…

Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)

EPSS: 0.000 (6.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Nyariv Sandboxjs — versions < 0.8.29

Weakness classification (CWE)

CWE-367 — Time-of-check Time-of-use (TOCTOU) Race Condition

References

https://github.com/nyariv/SandboxJS/security/advisories/GHSA-7x3h-rm86-3342 (x_refsource_CONFIRM)
https://github.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3 (x_refsource_MISC)
https://github.com/nyariv/SandboxJS/blob/6103d7147c4666fe48cfda58a4d5f37005b43754/src/executor.ts#L304-L304 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-25641?: CVE-2026-25641 is a critical-severity vulnerability in Nyariv Sandboxjs, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 10.0/10. Published 2026-02-06.
How severe is CVE-2026-25641?: Critical severity. CVSS v3 base score is 10.0 out of 10.