High severity · published Apr 6, 2026
CVE-2026-34211
SandboxJS: Stack overflow DoS via deeply nested expressions in recursive descent parser
7.5
CVSS
0.4%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SA
SandboxJS · nyariv
< 0.8.36 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34211
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34211
Exploit
https://github.com/nyariv/SandboxJS/security/advisories/GHSA-8pfc-jjgw-6g26
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