CVE-2025-38493
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-07-28

Last updated on: 2025-11-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: tracing/osnoise: Fix crash in timerlat_dump_stack() We have observed kernel panics when using timerlat with stack saving, with the following dmesg output: memcpy: detected buffer overflow: 88 byte write of buffer size 0 WARNING: CPU: 2 PID: 8153 at lib/string_helpers.c:1032 __fortify_report+0x55/0xa0 CPU: 2 UID: 0 PID: 8153 Comm: timerlatu/2 Kdump: loaded Not tainted 6.15.3-200.fc42.x86_64 #1 PREEMPT(lazy) Call Trace: <TASK> ? trace_buffer_lock_reserve+0x2a/0x60 __fortify_panic+0xd/0xf __timerlat_dump_stack.cold+0xd/0xd timerlat_dump_stack.part.0+0x47/0x80 timerlat_fd_read+0x36d/0x390 vfs_read+0xe2/0x390 ? syscall_exit_to_user_mode+0x1d5/0x210 ksys_read+0x73/0xe0 do_syscall_64+0x7b/0x160 ? exc_page_fault+0x7e/0x1a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e __timerlat_dump_stack() constructs the ftrace stack entry like this: struct stack_entry *entry; ... memcpy(&entry->caller, fstack->calls, size); entry->size = fstack->nr_entries; Since commit e7186af7fb26 ("tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure"), struct stack_entry marks its caller field with __counted_by(size). At the time of the memcpy, entry->size contains garbage from the ringbuffer, which under some circumstances is zero, triggering a kernel panic by buffer overflow. Populate the size field before the memcpy so that the out-of-bounds check knows the correct size. This is analogous to __ftrace_trace_stack().
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Meta Information
Published
2025-07-28
Last Modified
2025-11-19
Generated
2026-05-06
AI Q&A
2025-07-28
EPSS Evaluated
2026-05-05
NVD
CVE-2025-38493
Affected Vendors & Products
Showing 9 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel 6.16
linux linux_kernel 6.16
linux linux_kernel 6.16
linux linux_kernel 6.16
linux linux_kernel 6.16
linux linux_kernel 6.16
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-674 The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a kernel panic caused by a buffer overflow in the Linux kernel's tracing subsystem, specifically in the timerlat_dump_stack() function. The issue arises because the size field of a stack entry structure is not properly set before a memcpy operation, leading to an out-of-bounds write and subsequent kernel crash when using timerlat with stack saving.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash (kernel panic) when using the timerlat tool with stack saving enabled. This can lead to system instability, unexpected reboots, and potential loss of data or service availability.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by observing kernel panics related to timerlat with stack saving enabled. Specifically, look for dmesg output containing messages like 'memcpy: detected buffer overflow' and warnings referencing __fortify_report and timerlat_dump_stack. You can check the kernel logs using the command: dmesg | grep -i timerlat. Additionally, monitoring for kernel panics or crashes when running timerlat tools may indicate the presence of this issue.


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation steps include updating the Linux kernel to a version where this vulnerability is fixed (post commit e7186af7fb26). Avoid using timerlat with stack saving enabled until the patch is applied. Monitoring kernel logs for related errors and avoiding triggering the vulnerable code path can help reduce risk until the update is performed.


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