CVE-2026-97934 tracing: Fix memory corruption from a "STACKTRACE" histogram key
A local attacker with tracing access can trigger memory corruption and kernel panic via a specific histogram key configuration.
- 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-2026-97934?
CVE-2026-97934 is a memory corruption vulnerability in Linux, published on 25 Sep 2026. 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:
tracing: Fix memory corruption from a "STACKTRACE" histogram key
"cpu", "CPU", "stacktrace" and "STACKTRACE" are generic fields, defined with an offset and a size of zero so that the filter code can match them by name. parse_field() maps them onto their common_* equivalents for backward compatibility, but unlike the common_* names it hands the placeholder back to the caller instead of NULL.
create_hist_field() takes a non-NULL field as a promise that the record carries a stacktrace and picks HIST_FIELD_FN_STACK, so the __data_loc word is read from offset 0, that is from common_type, and its low 16 bits are followed as an offset into the record. What is found there becomes the length of an unbounded memcpy. Pick an event whose id is small enough that the offset stays inside its own record and the length is a kernel text address:
# cd /sys/kernel/tracing # echo 'hist:keys=STACKTRACE' > events/ftrace/print/trigger # echo hello > trace_marker
Oops: general protection fault, probably for non-canonical address RIP: 0010:rb_next+0x23/0x60 </IRQ> RIP: 0010:memcpy+0xc/0x30 event_hist_trigger+0x2e7/0x12c0 Kernel panic - not syncing: Fatal exception in interrupt
Leave the field NULL, which is what the comment above the branch says the code does and what common_stacktrace already does. FILTER_CPU and FILTER_COMM are left alone, their create_hist_field() branches never look at the field.
Which versions are affected by CVE-2026-97934?
How do I fix CVE-2026-97934?
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-2026-97934 being exploited?
There is no known exploitation of CVE-2026-97934 in the wild and no public exploit code.
Sources
Also known as AZL-104768, BELL-CVE-2026-97934, DEBIAN-CVE-2026-97934, GHSA-3wpw-vmp3-5ppq, UBUNTU-CVE-2026-97934.