CVE-2025-38636 rv: Use strings in da monitors tracepoints
A kernel bug causes out-of-bounds reads in tracepoints when KASAN is enabled, potentially leading to system crashes or instability.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38636?
CVE-2025-38636 is a high-severity memory corruption vulnerability in Linux kernel, published on 22 Aug 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
rv: Use strings in da monitors tracepoints
Using DA monitors tracepoints with KASAN enabled triggers the following warning:
BUG: KASAN: global-out-of-bounds in do_trace_event_raw_event_event_da_monitor+0xd6/0x1a0 Read of size 32 at addr ffffffffaada8980 by task ... Call Trace: <TASK> [...] do_trace_event_raw_event_event_da_monitor+0xd6/0x1a0 ? __pfx_do_trace_event_raw_event_event_da_monitor+0x10/0x10 ? trace_event_sncid+0x83/0x200 trace_event_sncid+0x163/0x200 [...] The buggy address belongs to the variable: automaton_snep+0x4e0/0x5e0
This is caused by the tracepoints reading 32 bytes __array instead of __string from the automata definition. Such strings are literals and reading 32 bytes ends up in out of bound memory accesses (e.g. the next automaton's data in this case). The error is harmless as, while printing the string, we stop at the null terminator, but it should still be fixed.
Use the __string facilities while defining the tracepoints to avoid reading out of bound memory.
Weakness: CWE-125
Which versions are affected by CVE-2025-38636?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-38636?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-38636 being exploited?
There is no known exploitation of CVE-2025-38636 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-66611, BELL-CVE-2025-38636, DEBIAN-CVE-2025-38636, GHSA-xg28-vm4v-pcgp, ROOT-OS-DEBIAN-12-CVE-2025-38636, ROOT-OS-DEBIAN-13-CVE-2025-38636 and 2 more.