CVE-2023-53435 – This CVE describes a memory leak vulnerability ... (How to Fix)

Q: What is the severity of CVE-2023-53435?

CVE-2023-53435 has a CVSS score of 5.5 (MEDIUM). This CVE describes a memory leak vulnerability in the Linux kernel's cassini network driver. When the cas_init_one() function fails during device initialization, it doesn't properly free memory allocated by vmalloc(), causing a kernel memory leak. This affects systems using the cassini driver for Sun Cassini network adapters.

📋 TL;DR

This CVE describes a memory leak vulnerability in the Linux kernel's cassini network driver. When the cas_init_one() function fails during device initialization, it doesn't properly free memory allocated by vmalloc(), causing a kernel memory leak. This affects systems using the cassini driver for Sun Cassini network adapters.

💻 Affected Systems

Products:

Linux kernel with cassini driver enabled

Versions: Linux kernel versions before the fix commits (specific versions vary by distribution)

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable if cassini driver is loaded/used (typically for Sun Cassini network adapters); many systems won't have this driver active by default.

📦 What is this software?

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

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Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Sustained exploitation could lead to kernel memory exhaustion, causing system instability, crashes, or denial of service through resource depletion.

🟠

Likely Case

Memory leak during device initialization failures, potentially causing gradual memory consumption and system performance degradation over time.

🟢

If Mitigated

Minimal impact with proper monitoring and memory limits; system remains functional but may experience performance issues during repeated device initialization failures.

🌐 Internet-Facing: LOW - Requires local access or ability to trigger device initialization failures; not directly exploitable over network.

🏢 Internal Only: MEDIUM - Requires local access or ability to trigger device probe failures; could be exploited by malicious local users or through other vulnerabilities.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires ability to trigger device initialization failures; may require local access or combination with other vulnerabilities.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Linux kernel versions containing the fix commits (11c0ed097a874156957b515d0ba7e356142eab87 and related)

Vendor Advisory: https://git.kernel.org/stable/c/11c0ed097a874156957b515d0ba7e356142eab87

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify cassini driver is not causing memory leaks.

🔧 Temporary Workarounds

Disable cassini driver

linux

Prevent loading of vulnerable cassini driver module

echo 'blacklist cassini' >> /etc/modprobe.d/blacklist.conf
rmmod cassini

🧯 If You Can't Patch

Monitor kernel memory usage for unusual increases
Restrict local user access to prevent triggering device initialization

🔍 How to Verify

Check if Vulnerable:

Check if cassini module is loaded: lsmod | grep cassini AND check kernel version against patched versions

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits AND monitor for memory leaks during device operations

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages
Memory allocation failures in dmesg
System logs showing repeated device initialization failures

Network Indicators:

None specific - this is a local memory issue

SIEM Query:

Search for: 'cassini' OR 'cas_init_one' in kernel logs with memory allocation errors

📊 Metadata

CVE ID: CVE-2023-53435

CVSS v3 Score: 5.5 (MEDIUM)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE: CWE-401

EPSS Score: 0.01% exploit probability (1.3th percentile)

Published: September 18, 2025

Last Updated: January 14, 2026

🔗 References

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