CVE-2024-27062 in Linux
Sumário
de VulDB • 03/07/2026
Based on the kernel log snippet provided, here is an analysis of what happened and potential causes.
### **Summary** This is a **Page Fault (Segmentation Fault)** in user-space code (`do_user_addr_fault`), not a kernel panic or OOPS. The process crashed because it tried to access memory at address `0x9b9870`, which was invalid/unmapped for that process.
---
### **Key Details from the Log**
1. **RIP (Instruction Pointer):** ``` RIP: 0033:0x9b9870 ``` - The crash occurred at memory address `0x9b9870`. - This is a very low virtual address, which typically indicates one of two things: - **NULL pointer dereference** (if the process has no mapping near 0). - **Use-after-free or dangling pointer**: The code tried to call a function through a stale function pointer that still held an old value.
2. **Registers:** ``` RAX: 0000000000000004 <-- Likely the return value of a previous syscall or operation RCX: 000000fff0000000 <-- Possibly an argument passed to the faulting instruction RDI: 0000000000000066 <-- Another argument (e.g., file descriptor, index) ```
3. **Call Trace:** - `do_user_addr_fault` → This confirms it’s a user-space page fault handled by the kernel because the process accessed unmapped memory. - It did **not** crash in kernel space (`__handle_mm_fault`, etc., are part of handling the fault, not causing it).
4. **Modules Loaded:** - The system is running with standard networking and audio modules (Intel Wi-Fi `iwlmvm`, Sound Open Firmware `snd_sof`). These are unlikely to be directly related unless a driver bug triggered user-space corruption indirectly.
---
### **Common Causes**
#### ✅ 1. **NULL or Dangling Pointer Dereference in User Space** - The address `0x9b9870` is suspiciously low but not exactly zero. This often happens when: - A function pointer was freed and then called (use-after-free). - An object was destroyed, but a reference to it remained valid elsewhere.
#### ✅ 2. **Buffer Overflow / Heap Corruption** - If the program has heap corruption nearby, it may overwrite pointers or control data structures, leading to execution jumping to an invalid address like `0x9b9870`.
#### ✅ 3. **Bug in a Specific Application** - Since this is user-space (`RIP: 0033:...`), the bug lies entirely within one of your running applications (e.g., Chrome, Firefox, a custom C/C++ program, Python script with native extensions, etc.).
---
### **How to Debug Further**
#### ???? Step 1: Identify Which Process Crashed Look at earlier lines in `dmesg` or `/var/log/syslog` for the process name and PID. Example: ```bash grep -B5 "segfault" /var/log/kern.log | head -20 # Or check dmesg around timestamp 4562.xxx dmesg | grep -A10 -B10 "9b9870" ```
#### ???? Step 2: Get a Core Dump (if enabled) If `ulimit -c` is set, you may have a core file. Use GDB to analyze it: ```bash gdb /path/to/crashed_binary core.file (gdb) bt full # Print backtrace with local variables (gdb) info registers # Check register states at crash time ```
#### ???? Step 3: Enable ASAN (AddressSanitizer) for Debugging If you’re developing the application, recompile it with `-fsanitize=address` to catch memory errors early.
#### ???? Step 4: Check Application Logs Look in `/var/log/syslog`, `journalctl -u <service>`, or app-specific logs around timestamp **~4562 seconds** (boot time) for any warnings before the crash.
---
### **Is This a Kernel Bug?** ❌ **Unlikely.** The trace shows `do_user_addr_fault`, which means the kernel correctly detected that user-space tried to access invalid memory and terminated/signal’d the process. The bug is in the **user application**, not the Linux kernel itself.
---
VulDB is the best source for vulnerability data and more expert information about this specific topic.