How severe is CVE-2026-26954?

CVE-2026-26954 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-26954 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-26954?

CVE-2026-26954 affects Nyariv Sandboxjs. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-26954?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-26954 have an EU (EUVD) identifier?

Yes. CVE-2026-26954 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12043.

When was CVE-2026-26954 published?

CVE-2026-26954 was published on 2026-03-13 and last updated on 2026-06-17.

CVE-2026-26954

CVE-2026-26954 is a critical-severity vulnerability in Nyariv Sandboxjs with a CVSS 3.x base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-12043
Weakness: CWE-94
Affected product: Nyariv Sandboxjs
Published: 2026-03-13
Last modified: 2026-06-17

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.34, it is possible to obtain arrays containing Function, which allows escaping the sandbox. Given an array containing Function, and Object.fromEntries, it is possible to construct {[p]: Function} where p is any constructible property. This vulnerability is fixed in 0.8.34.

Frequently asked questions

What is CVE-2026-26954?: SandboxJS is a JavaScript sandboxing library. Prior to 0.8.34, it is possible to obtain arrays containing Function, which allows escaping the sandbox. Given an array containing Function, and Object.fromEntries, it is possible to construct {[p]: Function} where p is any constructible property. This vulnerability is fixed in 0.8.34.
How severe is CVE-2026-26954?: CVE-2026-26954 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-26954 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-26954?: CVE-2026-26954 affects Nyariv Sandboxjs. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-26954?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-26954 have an EU (EUVD) identifier?: Yes. CVE-2026-26954 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12043.
When was CVE-2026-26954 published?: CVE-2026-26954 was published on 2026-03-13 and last updated on 2026-06-17.

References

https://github.com/nyariv/SandboxJS/security/advisories/GHSA-6r9f-759j-hjgv

Affected products (1)

cpe:2.3:a:nyariv:sandboxjs:*:*:*:*:*:node.js:*:*

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