Critical Linux Kernel Security Update for Oracle Cloud Systems (USN-7685-4)

 

Critical Linux kernel vulnerabilities (USN-7685-4) patched for Oracle Cloud systems. Exploits in Ext4, SMB, Bluetooth & more risk system compromise. Mandatory update & reboot required. Learn patch details, affected versions, & secure with Ubuntu Pro ESM. Free for 5 machines!

Urgent Security Advisory: Multiple high-severity vulnerabilities have been patched in the Oracle-specific Linux kernel, demanding immediate attention from cloud administrators and DevOps teams. 

Failure to patch exposes critical infrastructure to potential system compromise and data breaches. Are your Oracle Cloud instances shielded against the latest zero-day exploits?

Overview: Critical Flaws Patched

The Ubuntu Security Team has resolved numerous critical security weaknesses within the Linux kernel packages specifically tailored for Oracle Cloud environments. 

These vulnerabilities, spanning multiple core subsystems, could be exploited by attackers to gain unauthorized access, escalate privileges, or cause denial-of-service conditions. 

This patch release (USN-7685-4) is classified as essential for maintaining system integrity and compliance standards like PCI-DSS and HIPAA in cloud deployments.

Affected Subsystems & Threat Landscape
The patched vulnerabilities impact fundamental components of the kernel, significantly increasing the attack surface if unmitigated. Key areas addressed include:

• Hardware Interface Risks: Flaws in the Device Tree & Open Firmware drivers could allow hardware-level manipulation.

• Data Storage Threats: Vulnerabilities within the SCSI subsystem and the Ext4 filesystem risk data corruption or unauthorized access.

• Input/Output Exploits: TTY driver weaknesses could enable keystroke logging or terminal hijacking.

• Network Attack Vectors: Critical bugs patched in the SMB network filesystem, Bluetooth stack, Network Traffic Control (Netfilter/tc), and Sun RPC protocol expose systems to remote code execution and man-in-the-middle attacks.

• Peripheral Compromise: USB sound device drivers contained exploitable flaws.

Impact Assessment: Successful exploitation of these CVEs could lead to full system compromise, sensitive data exfiltration, or crippling service outages. The inclusion of recent CVEs (e.g., CVE-2025-37797, CVE-2024-56748) underscores the ongoing discovery of sophisticated kernel-level threats targeting cloud infrastructure.

Mandatory Update Instructions
Action Required: A system reboot is non-negotiable after applying these kernel updates to activate the security fixes.

1. Update Packages: Apply the updates using your standard package management tools (sudo apt update && sudo apt upgrade).

2. Reboot: Execute sudo reboot immediately after the update completes.

3. Kernel Module Recompilation (Critical): ATTENTION: This update introduces an unavoidable ABI change.

• Automatic Handling: If you haven't manually removed standard kernel metapackages (e.g., linux-generic, linux-generic-lts-18.04, linux-virtual, linux-powerpc), your system should automatically handle recompiling and reinstalling DKMS (Dynamic Kernel Module Support) modules during the upgrade.

• Manual Intervention: If you use custom or third-party kernel modules (e.g., proprietary drivers, ZFS, NVIDIA drivers, VPN clients) outside DKMS, you MUST manually recompile and reinstall them against the new kernel headers (linux-headers-...-oracle). Failure will likely result in module failures upon reboot.

Affected Package Versions:

Ubuntu Release	Package Name	Secure Version
18.04 LTS (Bionic)	linux-image-4.15.0-1145-oracle	4.15.0-1145.156
18.04 LTS (Bionic)	linux-image-oracle-4.15	4.15.0.1145.150
18.04 LTS (Bionic)	linux-image-oracle-lts-18.04	4.15.0.1145.150

Proactive Threat Mitigation with Ubuntu Pro

Why constantly react to vulnerabilities when you can proactively reduce your attack surface? Ubuntu Pro delivers enterprise-grade security hardening and an unprecedented ten-year security maintenance commitment for over 25,000 packages in Main and Universe repositories.

• Extended Security Maintenance (ESM): Critical security patches for the kernel and essential libraries long after standard support ends.

• Kernel Livepatching: Apply critical kernel security fixes without rebooting, maximizing uptime and operational continuity.

• FIPS 140-2 Certified Modules: Meet stringent government and industry compliance requirements.

• System Hardening Profiles: Enforce CIS and DISA-STIG benchmarks automatically.

• Free for Up to 5 Machines: Secure your critical infrastructure at no initial cost.

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Vulnerability References (CVEs Patched):

• CVE-2025-37797

• CVE-2024-56748

• CVE-2024-53239

• CVE-2024-50073

• CVE-2024-49950

• CVE-2024-49883

• CVE-2024-38541

• CVE-2023-52975

• CVE-2023-52885

• CVE-2023-52757

(Internal Link Suggestion: Learn more about [Linux kernel vulnerability management best practices] on our security hub.)

Why This Matters for Enterprise Cloud Security

Kernel vulnerabilities represent the most severe threat level in Linux environments. As the core interface between hardware and software, a compromised kernel grants attackers near-unlimited control. 

Oracle Cloud environments, often hosting sensitive workloads, are prime targets. This patch cycle highlights the continuous evolution of offensive security tactics, demanding a robust, layered defense strategy incorporating timely patching, kernel hardening, and runtime protection.

Frequently Asked Questions (FAQ)

• Q1: How urgent is this update?

• A: Extremely urgent. Several vulnerabilities have known exploits or are easily weaponizable. Apply and reboot immediately.

• Q2: I use containers. Am I still vulnerable?

• A: Yes. Container escapes exploiting kernel vulnerabilities are a well-documented threat. Securing the host kernel is paramount for container security.

• Q3: What if I can't reboot immediately?

• A: The risk is significant. Utilize Ubuntu Pro's Livepatch if available for critical vulnerabilities to mitigate risk until a maintenance window. This is not a permanent solution.

• Q4: Where can I learn more about the technical details of these CVEs?

• A: Refer to the Ubuntu CVE Tracker or the National Vulnerability Database (NVD) for detailed analysis of each CVE.

• Q5: Does Ubuntu Pro cover older LTS releases like 18.04?

  • A: Yes! Ubuntu Pro provides extended security maintenance specifically for LTS releases like 18.04 Bionic, ensuring ongoing protection long after the standard 5-year period.

Conclusion & Next Steps

The USN-7685-4 update addresses critical attack vectors within the Oracle-optimized Linux kernel. Prompt application is non-negotiable for maintaining the confidentiality, integrity, and availability of your cloud systems. 

Combine this essential patching with the proactive, comprehensive security posture offered by Ubuntu Pro to significantly reduce your exposure to evolving threats and ensure long-term platform stability.

Take Action Now:

1. Patch: Update your linux-oracle packages immediately.

2. Reboot: Schedule or execute a necessary reboot.

3. Verify Modules: Confirm third-party kernel modules function post-update.

4. Harden: Activate Ubuntu Pro for continuous, deep security coverage.
   > > Secure Your Systems with Ubuntu Pro - Free for 5 Machines <<