CVE-2025-38702 – A buffer overflow vulnerability exists in the L... (How to Fix)

Q: What is the severity of CVE-2025-38702?

CVE-2025-38702 has a CVSS score of 7.8 (HIGH). A buffer overflow vulnerability exists in the Linux kernel's framebuffer device driver (fbdev) in the do_register_framebuffer() function. This allows local attackers to potentially execute arbitrary code or crash the system by triggering an out-of-bounds array access. All Linux systems using the affected kernel versions with framebuffer support are vulnerable.

📋 TL;DR

A buffer overflow vulnerability exists in the Linux kernel's framebuffer device driver (fbdev) in the do_register_framebuffer() function. This allows local attackers to potentially execute arbitrary code or crash the system by triggering an out-of-bounds array access. All Linux systems using the affected kernel versions with framebuffer support are vulnerable.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected versions not explicitly stated in CVE; typically multiple stable kernel branches before fixes were backported.

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires framebuffer device support (CONFIG_FB) which is commonly enabled in desktop/server kernels. Embedded systems with graphics may be affected.

📦 What is this software?

Debian Linux by Debian

View all CVEs affecting Debian Linux →

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 →

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

Local privilege escalation to kernel-level code execution, leading to complete system compromise, data theft, or persistent backdoor installation.

🟠

Likely Case

Kernel panic leading to system crash and denial of service, requiring physical or remote console access to reboot.

🟢

If Mitigated

System remains stable if framebuffer functionality is disabled or unused, or if kernel hardening features like KASLR/SMAP/SMEP prevent exploitation.

🌐 Internet-Facing: LOW - This is a local kernel vulnerability requiring local access; not directly exploitable over network.

🏢 Internal Only: MEDIUM - Local users or compromised accounts could exploit this for privilege escalation or DoS attacks on affected systems.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and ability to interact with framebuffer devices. Exploitation depends on specific kernel configuration and memory layout.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits: 248b2aab9b2af5ecf89d9d7955a2ff20c4b4a399, 2828a433c7d7a05b6f27c8148502095101dd0b09, 523b84dc7ccea9c4d79126d6ed1cf9033cf83b05, 5c3f5a25c62230b7965804ce7a2e9305c3ca3961, 806f85bdd3a60187c21437fc51baace11f659f35

Vendor Advisory: https://git.kernel.org/stable/c/248b2aab9b2af5ecf89d9d7955a2ff20c4b4a399

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from distribution vendor. 2. For custom kernels, apply the fix commits from kernel git repository. 3. Rebuild and install kernel. 4. Reboot system to load patched kernel.

🔧 Temporary Workarounds

Disable framebuffer support

linux

Remove framebuffer device support from kernel configuration to eliminate attack surface.

Rebuild kernel with CONFIG_FB=n in kernel configuration

Restrict framebuffer device access

linux

Use filesystem permissions to limit access to /dev/fb* devices to trusted users only.

chmod 600 /dev/fb*
chown root:root /dev/fb*

🧯 If You Can't Patch

Implement strict access controls to limit local user accounts and prevent untrusted users from accessing the system.
Deploy kernel hardening features like SELinux/AppArmor to restrict framebuffer device operations and contain potential exploits.

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if framebuffer devices exist: 'ls -la /dev/fb*' and 'uname -r' to compare against patched versions.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated to include fix commits, and test framebuffer functionality remains operational without crashes.

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages in /var/log/kern.log or dmesg output related to fbdev or general protection faults
System crash/reboot logs without clear cause

Network Indicators:

None - this is local exploitation only

SIEM Query:

source="kernel" AND ("fbdev" OR "general protection fault" OR "Oops")

📊 Metadata

CVE ID: CVE-2025-38702

CVSS v3 Score: 7.8 (HIGH)

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

CWE: CWE-787

EPSS Score: 0.02% exploit probability (2.7th percentile)

Published: September 4, 2025

Last Updated: January 23, 2026

🔗 References

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