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CVE-2026-34211

Nyariv Sandboxjs denial of service

7.5 HIGHPublic exploitEPSS 0.49%
  1. Published6 Apr 2026

Description

SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, the @nyariv/sandboxjs parser contains unbounded recursion in the restOfExp function and the lispify/lispifyExpr call chain. An attacker can crash any Node.js process that parses untrusted input by supplying deeply nested expressions (e.g., ~2000 nested parentheses), causing a RangeError: Maximum call stack size exceeded that terminates the process. This vulnerability is fixed in 0.8.36.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Nyariv Sandboxjs< 0.8.36

Remediation

Fixed in
Nyariv Sandboxjs≥ 0.8.36

References

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Frequently asked

Is CVE-2026-34211 being actively exploited?

CVE-2026-34211 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.49%.

How severe is CVE-2026-34211?

CVE-2026-34211 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.49% probability of exploitation.

Which products are affected by CVE-2026-34211?

Affected products include Nyariv Sandboxjs.

How do I fix CVE-2026-34211?

Upgrade affected software to a fixed version, for example Nyariv Sandboxjs 0.8.36 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-34211 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.