A vulnerability in JumpCloud Remote Assist for Windows could allow attackers to escalate privileges and potentially take over endpoints.

The bug exists because, during uninstall and update operations, the application invokes an uninstaller that performs privileged operations on a directory the user controls.

The flaw, tracked as CVE-2025-34352 (CVSS score of 8.5), can be triggered during the removal or update of the JumpCloud Agent.

“The Remote Assist uninstaller performs privileged create, write, execute, and delete actions on predictable files inside a user-writable %TEMP% subdirectory without validating that the directory is trusted or resetting its ACLs when it already exists,” a NIST advisory reads.

This enables an unprivileged local attacker to pre-create the directory, on which the uninstaller then performs operations with NT AUTHORITY\SYSTEM privileges.

According to XM Cyber, which identified the vulnerability, attackers can rely on symbolic links and mount-point redirections to trick the uninstaller into performing operations on protected system files.

The JumpCloud Agent, the cybersecurity firm notes, dynamically builds the full path to the Remote Assist folder, using environment variables, and looks for the uninstaller binary in that folder.

Every time the agent is removed, it removes JumpCloud Remote Assist and all other components.

In short, the privileged JumpCloud process performs delete, write, and execute operations on files with predictable filenames, from an untrusted path.

Using mount points and symbolic links, the attacker redirects the privileged operation and writes arbitrary data to any file, including system files, which has two outcomes.

On the one hand, by utilizing a Mount Point/Object Manager namespace attack, a threat actor can write data to the System32\cng.sys driver, which would result in an infinite Blue Screen of Death (BSOD).

On the other hand, an attacker can abuse a Time-of-Check to Time-of-Use (TOCTOU) race condition to delete the content of the Config.Msi folder, replace it, and then use a Windows Installer LPE technique to execute a System shell.

The vulnerability was addressed in JumpCloud Remote Assist for Windows version 0.317.0. Organizations are advised to update to it as soon as possible.

“For vendor risk assessment, confirm that no privileged process executes arbitrary code, reads, or writes to a user-writable directory (like %TEMP%) without explicitly setting or overriding the folder’s Access Control Lists (ACLs),” XM Cyber notes.

A JumpCloud spokesperson provided the following statement to SecurityWeek:

“JumpCloud was aware of a security vulnerability (CVE-2025-34352) discovered and patched in an older version of JumpCloud’s Remote Assist Agent (RAA). Ensuring our customers’ environments are secure is our highest priority, so JumpCloud automatically upgraded all customers’ RAA versions to 0.319.0 in late October.
A security researcher had responsibly disclosed it to JumpCloud and worked with our team throughout the process.
Following the upgrade, JumpCloud performed a comprehensive audit and confirmed all customer environments had the patch applied.”

*Updated with statement from JumpCloud.

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