CVE-2026-34217
Nyariv Sandboxjs ≤ 0.8.36
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/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:XSummary
CVE-2026-34217 is a medium-severity Exposure of Resource to Wrong Sphere (CWE-668) vulnerability in Nyariv Sandboxjs. Its CVSS base score is 6.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Cloud Instance Metadata API (T1552.005); ranked at the 22th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34217 is a scope modification vulnerability in SandboxJS, a JavaScript sandboxing library distributed as @nyariv/sandboxjs. Versions prior to 0.8.36 are affected, where untrusted sandboxed code can leak internal interpreter objects through the new operator. This exposes sandbox scope objects in the scope hierarchy to the untrusted code, representing an unexpected exploit primitive. The issue is rated with a CVSS v3.1 base score of 7.2 (AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N) and maps to CWE-668 (Exposure of Resource to Wrong Sphere).
The vulnerability can be exploited by any attacker who can supply untrusted JavaScript code to be executed within a SandboxJS sandbox. Exploitation occurs remotely over a network with low complexity and no privileges or user interaction required, but it changes scope. Successful exploitation allows the untrusted code to access and potentially modify scopes inside the sandbox, though code evaluation remains sandboxed and prototypes stay protected, limiting the impact to low confidentiality and integrity violations without availability effects.
The GitHub security advisory (GHSA-hg73-4w7g-q96w) confirms the vulnerability is fixed in SandboxJS version 0.8.36, recommending that users upgrade to this or later versions to mitigate the issue. No additional workarounds are specified in the provided references.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-19301
Vulnerability Data
SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, a scope modification vulnerability exists in @nyariv/sandboxjs. The vulnerability allows untrusted sandboxed code to leak internal interpreter objects through the new operator, exposing sandbox scope objects in the scope hierarchy to…
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untrusted code; an unexpected and undesired exploit. While this could allow modifying scopes inside the sandbox, code evaluation remains sandboxed and prototypes remain protected throughout the execution. This vulnerability is fixed in 0.8.36.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 8 hardening rules · 7 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Access enforcement directly stops resources from being reachable by actors outside the intended control sphere.
Information flow enforcement structurally prevents unintended cross-sphere data or resource exposure.
Least privilege reduces the set of actors that can reach a resource, limiting wrong-sphere exposure.
Security attributes enable correct sphere assignment and subsequent enforcement decisions.
Boundary protection at interfaces prevents resources from being exposed outside authorized spheres.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Enforcing least-privilege authorizations directly prevents resources from being exposed outside their intended control sphere.
Network segmentation and unauthorized-access protections reduce the chance of resources being reachable by the wrong sphere.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Placing systems of differing trust levels into separate domains prevents resources from being placed in a sphere where they are reachable by unintended actors.
Requiring owners to manage the full asset life cycle and remove assets from the inventory upon secure disposal helps prevent resources from being inadvertently exposed outside their intended security sphere.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-668
- V-248823 OL 8 must not have the telnet-server package installed. prevents CWE-668
RHEL 7 (1 rule)
- V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-668
Windows 10 (1 rule)
- V-220967 The Debug programs user right must only be assigned to the Administrators group. prevents CWE-668
Windows 11 (1 rule)
- V-253490 The "Debug programs" user right must only be assigned to the Administrators group. prevents CWE-668
Windows Server 2016 (1 rule)
- V-225079 The Debug programs user right must only be assigned to the Administrators group. prevents CWE-668
Windows Server 2019 (1 rule)
- V-205757 Windows Server 2019 Debug programs: user right must only be assigned to the Administrators group. prevents CWE-668
Windows Server 2022 (1 rule)
- V-254500 Windows Server 2022 debug programs user right must only be assigned to the Administrators group. prevents CWE-668