CVE-2025-38636
📋 TL;DR
This CVE describes a kernel memory access vulnerability in Linux's Runtime Verification (RV) subsystem where DA monitors tracepoints incorrectly read 32-byte fixed arrays instead of null-terminated strings. This causes out-of-bounds memory reads when KASAN (Kernel Address Sanitizer) is enabled, potentially exposing adjacent kernel memory. The vulnerability affects Linux systems with RV subsystem enabled and KASAN active.
💻 Affected Systems
- Linux kernel
📦 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...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Information disclosure of adjacent kernel memory structures, potentially revealing sensitive kernel data or pointers that could aid further exploitation.
Likely Case
Kernel warning/panic when KASAN is enabled, causing system instability or crashes. Without KASAN, the bug is mostly harmless as reads stop at null terminators.
If Mitigated
Minimal impact if KASAN is disabled or RV subsystem is not in use.
🎯 Exploit Status
Exploitation requires local access and ability to trigger RV tracepoints. The vulnerability primarily causes information disclosure rather than code execution.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in kernel commits 0ebc70d973ce7a81826b5c4f55f743e07f5864d9 and 7f904ff6e58d398c4336f3c19c42b338324451f7
Vendor Advisory: https://git.kernel.org/stable/c/0ebc70d973ce7a81826b5c4f55f743e07f5864d9
Restart Required: Yes
Instructions:
1. Update to a kernel version containing the fix commits. 2. Check with your Linux distribution for security updates. 3. Rebuild kernel if compiling from source. 4. Reboot system to load patched kernel.
🔧 Temporary Workarounds
Disable KASAN
linuxDisable Kernel Address Sanitizer to prevent the out-of-bounds detection and system instability
Rebuild kernel with CONFIG_KASAN=n or boot with 'kasan=off' kernel parameter
Disable RV subsystem
linuxDisable Runtime Verification subsystem if not required
Rebuild kernel with CONFIG_RV=n or boot with 'rv=off' module parameter if available
🧯 If You Can't Patch
- Disable KASAN in production environments where it's not required for debugging
- Restrict local user access to systems and monitor for unusual kernel warnings/crashes
🔍 How to Verify
Check if Vulnerable:
Check if kernel has RV subsystem and KASAN enabled: grep -E 'CONFIG_RV|CONFIG_KASAN' /boot/config-$(uname -r)Check Version:
uname -rVerify Fix Applied:
Check kernel version includes fix commits: uname -r and verify with distribution security advisories📡 Detection & Monitoring
Log Indicators:
- KASAN warnings about global-out-of-bounds reads
- Kernel panic messages related to RV tracepoints
- dmesg output showing 'BUG: KASAN: global-out-of-bounds'
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for kernel logs containing 'KASAN: global-out-of-bounds' AND 'event_da_monitor' OR 'automaton_snep'