CVE-2026-120338 Prefab UI - Unrestricted File Read & Write and Remote Code Execution

Prefab UI 0.14.0 through 0.20.2 contains a file system read and write vulnerability caused by unrestricted Deno permissions and exposed Deno API in the JavaScript global object, letting attackers with code execution read/write files as the server OS user and persist code execution, exploit requires ability to supply code to the sandbox.

CVSS base score 10.0 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.77% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Unrestricted File Read
Impact
File System Read, File System Write, Remote Code Execution
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Published
1 November 2026
Updated
3 November 2026
Weakness
CWE-94

Vendor fix

Upgrade to version 0.21.0 or later where Deno permissions are revoked before code execution and network access is limited.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

← All CVEs