JVM Classpath Hijacking via Temporary Directory Manipulation

Executive Summary

CVE-2025-11919 is a vulnerability in Wolfram Cloud version 14.2 that arises from insecure handling of the shared /tmp/ directory in a multi-tenant cloud environment. During the Java Virtual Machine (JVM) initialization, the JVM accesses files and directories under /tmp/, including temporary directories of other users. An attacker with access to this shared space can create or replace .jar files or directories that the JVM will load first in its classpath, such as a malicious version of a commonly used library like commons-io.

By exploiting this race condition, the attacker can cause the JVM to load and execute malicious code during startup, leading to arbitrary code execution within the victim's JVM process.

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Detection Guidance

Detection of this vulnerability involves checking for unauthorized or suspicious files in the shared /tmp/ directory, especially looking for malicious .jar files or -init files that could be used to manipulate the JVM classpath.

You can list files in the /tmp/ directory and subdirectories related to other users' temporary files to identify unexpected or suspicious entries.

• Use commands like `ls -la /tmp/` and `find /tmp/ -name '*.jar'` to locate potentially malicious jar files.
• Check for the presence of -init files in /tmp/ directories with `find /tmp/ -name '*-init*'`.
• Monitor JVM startup logs for unusual classpath entries or errors indicating loading of unexpected libraries.

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Impact Analysis

This vulnerability can have severe impacts including privilege escalation, information disclosure, and remote code execution within the affected cloud environment.

• Attackers can gain unauthorized access to other users' temporary directories.
• They can execute arbitrary malicious code in the context of another user's JVM process.
• This can lead to data exfiltration and lateral movement within the shared cloud environment.
• The attack requires no user interaction and can be triggered predictably if the attacker knows when other users launch Java processes.

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Compliance Impact

The vulnerability allows attackers to gain unauthorized access to other users' temporary directories and execute arbitrary code, which can lead to privilege escalation and data exfiltration.

Such unauthorized access and potential data disclosure can impact compliance with data protection regulations like GDPR and HIPAA, which require strict controls over access to personal and sensitive data.

Failure to prevent unauthorized access and data breaches due to this vulnerability could result in violations of these standards, leading to legal and regulatory consequences.

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Mitigation Strategies

Immediate mitigation steps include restricting access to the shared /tmp/ directory to prevent unauthorized users from creating or replacing files.

Hardening the JVM classpath resolution process to avoid loading malicious libraries from untrusted locations is critical.

Implement per-user sandboxing to isolate temporary directories and prevent cross-user access.

Upgrade Wolfram Cloud to version 14.2.1 or later, where this vulnerability has been patched.

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