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Fencer Vulns
high 7.0

CVE-2025-34146 json

nyariv sandboxjs 0.8.23 Prototype Pollution Sandbox Escape DoS

published 2025-07-31 15 mo ago modified 2026-10-08 31 d ago also EUVD-2025-23278 , GHSA-9qm3-6qrr-c76m

cvss
7.0
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

A prototype pollution vulnerability exists in @nyariv/sandboxjs versions <= 0.8.23, allowing attackers to inject arbitrary properties into Object.prototype via crafted JavaScript code. This can result in a denial-of-service (DoS) condition or, under certain conditions, escape the sandboxed environment intended to restrict code execution. The vulnerability stems from insufficient prototype access checks in the sandbox’s executor logic, particularly in the handling of JavaScript function objects returned.

Patch / fix

  • npm @nyariv/sandboxjs 0.8.24
  • nyariv sandboxjs 0.8.24

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • gist.github.com https://gist.github.com/Hagrid29/9df27829a491080f923c4f6b8518d7e3 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 7.0 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 4.0 7.0 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
npm @nyariv/sandboxjs
<0.8.24
0.8.24

Affected products

  • nyariv sandboxjs

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.