CVE-2025-1272: Linux Kernel Information Disclosure Flaw

CVE-2025-1272 Overview

A security misconfiguration vulnerability has been identified in the Linux Kernel affecting Fedora Linux systems running kernel versions 6.12 and above. The kernel lockdown mode, a critical security feature designed to restrict access to sensitive kernel interfaces, is disabled without any warning on affected systems. This vulnerability allows attackers with local access and elevated privileges to access sensitive kernel memory mappings, I/O ports, BPF subsystems, and kprobes. More critically, the disabled lockdown mode permits loading of unsigned kernel modules, enabling execution of untrusted code and effectively bypassing Secure Boot protections.

Critical Impact

Attackers can load unsigned kernel modules, access sensitive kernel memory mappings, and bypass Secure Boot protections on affected Fedora Linux systems running kernel 6.12+.

Affected Products

• Fedora Linux with kernel version 6.12 and above
• Linux Kernel 6.12+ on Fedora Linux distributions
• Systems relying on Secure Boot protection with affected Fedora kernel versions

Discovery Timeline

• 2026-02-18 - CVE-2025-1272 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2025-1272

Vulnerability Analysis

The Linux Kernel lockdown mode is a security mechanism introduced to restrict root-level access to kernel features that could be used to modify the running kernel or load arbitrary code. When properly enabled, lockdown mode prevents access to /dev/mem, /dev/kmem, I/O port access, loading of unsigned kernel modules, and usage of certain debugging interfaces like kprobes and BPF.

In affected Fedora Linux systems running kernel versions 6.12 and above, the lockdown mode is inadvertently disabled during the boot process without generating any warning to system administrators. This creates a silent security gap where systems believed to be protected by lockdown mode and Secure Boot are actually vulnerable to kernel-level attacks.

The vulnerability requires local access with high privileges to exploit, but the potential impact is severe. An attacker who gains privileged access can leverage the disabled lockdown mode to load unsigned kernel modules, essentially gaining arbitrary code execution at the kernel level. This completely undermines the integrity guarantees provided by Secure Boot.

Root Cause

The root cause of this vulnerability lies in a misconfiguration or regression in the Fedora Linux kernel build process for version 6.12 and later releases. The kernel lockdown security feature, which should be enabled by default on systems utilizing UEFI Secure Boot, fails to activate properly. This appears to be a build-time or boot-time configuration issue specific to Fedora's kernel packaging rather than an upstream Linux kernel defect.

Attack Vector

This vulnerability requires local access to the affected system with high-level privileges. The attack scenario involves an attacker who has already gained privileged access to a Fedora Linux system leveraging the disabled lockdown mode to:

1. Load unsigned kernel modules containing malicious code
2. Access kernel memory mappings via /dev/mem or /dev/kmem
3. Utilize I/O port access for hardware-level attacks
4. Deploy malicious BPF programs or kprobes for kernel-level surveillance or manipulation

The vulnerability effectively transforms a system that appears to have Secure Boot protections into one that allows arbitrary kernel code execution, making it particularly dangerous in environments where Secure Boot is a compliance requirement.

Detection Methods for CVE-2025-1272

Indicators of Compromise

• Unexpected unsigned kernel modules loaded on the system (check with lsmod and verify signatures)
• Access attempts to /dev/mem or /dev/kmem from non-standard processes
• Unusual BPF programs or kprobes registered on the system
• Evidence of I/O port access from userspace applications

Detection Strategies

• Query the current lockdown status by checking /sys/kernel/security/lockdown - if it shows "none" on a Secure Boot system, the vulnerability is present
• Monitor for insmod or modprobe operations loading modules without valid signatures
• Use SentinelOne Singularity platform to detect unauthorized kernel module loading and suspicious kernel-level activity
• Implement audit rules for accesses to sensitive kernel interfaces like /dev/mem

Monitoring Recommendations

• Configure auditd rules to log all attempts to load kernel modules: auditctl -w /sbin/insmod -p x -k kernel_modules
• Enable alerting on kernel-level changes via SentinelOne's behavioral AI detection
• Regularly verify Secure Boot and lockdown status as part of security posture assessments
• Monitor for unexpected changes to kernel memory mappings or new BPF programs

How to Mitigate CVE-2025-1272

Immediate Actions Required

• Verify if your Fedora Linux systems are running kernel version 6.12 or above using uname -r
• Check the current lockdown status by reading /sys/kernel/security/lockdown
• Apply the security patches referenced in Red Hat Security Errata RHSA-2025:6966
• Consider temporarily using an older kernel version (pre-6.12) while waiting for patches on critical systems

Patch Information

Red Hat has released security updates to address this vulnerability. System administrators should apply the patches referenced in Red Hat Security Errata RHSA-2025:6966. Additional details about the vulnerability can be found in the Red Hat CVE-2025-1272 Details page. The issue is also tracked in Red Hat Bug Report #2345615.

Workarounds

• Enable lockdown mode manually via kernel boot parameter by adding lockdown=integrity or lockdown=confidentiality to the kernel command line in GRUB
• Restrict local privileged access to affected systems until patches are applied
• Implement additional module signing enforcement policies if possible
• Use SentinelOne runtime protection to monitor and block unauthorized kernel module loading attempts

# Verify current lockdown status
cat /sys/kernel/security/lockdown

# Add lockdown parameter to GRUB configuration
# Edit /etc/default/grub and add to GRUB_CMDLINE_LINUX:
# lockdown=integrity
# Then run: grub2-mkconfig -o /boot/grub2/grub.cfg

# Verify kernel version
uname -r