CVE-2024-36940

Q: What is the severity of CVE-2024-36940?

CVE-2024-36940 has a CVSS score of 7.8 (HIGH). This CVE describes a double-free vulnerability in the Linux kernel's pinctrl subsystem. The pinctrl_enable() function incorrectly frees a devm-managed pointer that is already automatically freed by devm_pinctrl_dev_release(), potentially leading to memory corruption. This affects all Linux systems using vulnerable kernel versions with the pinctrl subsystem enabled.

7.8 HIGH

📋 TL;DR

This CVE describes a double-free vulnerability in the Linux kernel's pinctrl subsystem. The pinctrl_enable() function incorrectly frees a devm-managed pointer that is already automatically freed by devm_pinctrl_dev_release(), potentially leading to memory corruption. This affects all Linux systems using vulnerable kernel versions with the pinctrl subsystem enabled.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected versions not explicitly stated in CVE description; check kernel commit history for exact ranges.

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with pinctrl subsystem enabled (common on embedded and many server systems).

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic, system crash, or potential privilege escalation if an attacker can trigger the double-free and control subsequent memory allocations.

🟠

Likely Case

System instability, kernel crashes, or denial of service when pinctrl operations are performed.

🟢

If Mitigated

No impact if the vulnerability is not triggered through pinctrl operations.

🌐 Internet-Facing: LOW - Requires local access or ability to execute code on the system.

🏢 Internal Only: MEDIUM - Local users or processes could potentially trigger the vulnerability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires triggering specific pinctrl operations and controlling memory layout; no public exploits known.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits: 288bc4aa75f150d6f1ee82dd43c6da1b438b6068, 41f88ef8ba387a12f4a2b8c400b6c9e8e54b2cca, 5038a66dad0199de60e5671603ea6623eb9e5c79, 558c8039fdf596a584a92c171cbf3298919c448c, 735f4c6b6771eafe336404c157ca683ad72a040d

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

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable pinctrl subsystem

linux

Remove or disable pinctrl module if not required (may break hardware functionality)

modprobe -r pinctrl_core
echo 'blacklist pinctrl_core' > /etc/modprobe.d/blacklist-pinctrl.conf

🧯 If You Can't Patch

Restrict local user access to prevent untrusted users from triggering pinctrl operations
Implement strict process isolation and limit system calls that could trigger the vulnerability

🔍 How to Verify

Check if Vulnerable:

Check kernel version and compare with patched commits: uname -r and examine kernel source for vulnerable code

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes the fix commits: grep -r 'pinctrl_enable' /usr/src/linux-source-*/drivers/pinctrl/core.c

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
Oops messages related to pinctrl or memory corruption
System crashes during pinctrl operations

Network Indicators:

None - local vulnerability only

SIEM Query:

source="kernel" AND ("pinctrl" OR "double free" OR "kernel panic")

📊 Metadata

CVE ID: CVE-2024-36940

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-415

Published: May 30, 2024

Last Updated: January 10, 2025

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Debian Linux by Debian

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Disable pinctrl subsystem

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

🔗 Related Vulnerabilities