CVE-2026-99247
tracing: Do not initialize tracefs work if tracing is disabled
What happened?
In the Linux kernel, the following vulnerability has been resolved:
tracing: Do not initialize tracefs work if tracing is disabled
If trace buffer allocation fails during early boot (e.g. in early_trace_init() -> allocate_trace_buffers()), tracing_disabled is left set to 1 and the global trace array events list remains uninitialized.
Later during boot, tracer_init_tracefs() (invoked via fs_initcall) queues tracerfs_init_work asynchronously without checking if tracing was disabled. When tracer_init_tracefs_work_func() runs, it calls event_trace_init() and init_tracer_tracefs(&global_trace, NULL) unconditionally. This leads to __find_event_file() dereferencing an uninitialized tr->events list, causing an early boot NULL pointer dereference Oops:
BUG: Kernel NULL pointer dereference on read at 0x00000010 Faulting instruction address: 0xc000000000485be0 Oops: Kernel access of bad area, sig: 7 [#1] ... NIP [c000000000485be0] __find_event_file+0x70/0x3c0 LR [c000000000448874] init_tracer_tracefs+0x274/0xc80 Call Trace: init_tracer_tracefs+0x274/0xc80 tracer_init_tracefs_work_func+0x50/0x320 process_one_work+0x1e8/0x5c0 worker_thread+0x1dc/0x3d0 kthread+0x194/0x1b0 start_kernel_thread+0x14/0x18
Check tracing_disabled at the beginning of tracer_init_tracefs_work_func() and return immediately if tracing is disabled or failed to initialize, preventing the crash.
Affected software and versions
| Software | Version information | Fixed version |
|---|---|---|
| LinuxLinux | affected: 6621a7004684bfcff5af4c8e4d37989941f42a6b to < e8665e884e076d894f3eed8b9ea28e37a6448604; affected: 6621a7004684bfcff5af4c8e4d37989941f42a6b to < e8cfcd7e60eaa3b0dea4d71c64499604e7081736; affected: 6621a7004684bfcff5af4c8e4d37989941f42a6b to < afd38b10b1c6a5c5d6952b15b990596dab9684e6; affected: 6621a7004684bfcff5af4c8e4d37989941f42a6b to < 813e18881c6472eb229a63180ff42c808e3e949b; affected: 6621a7004684bfcff5af4c8e4d37989941f42a6b to < 7539c61f522ff693d9565a0411386c2236e776cd; affected: 6621a7004684bfcff5af4c8e4d37989941f42a6b to < b3b974008388ab59e44d764ba7a63c988fec2524 | See vendor advisory |
| LinuxLinux | affected: 5.19; unaffected: 0 to < 5.19; unaffected: 6.1.191 to ≤ 6.1.*; unaffected: 6.6.161 to ≤ 6.6.*; unaffected: 6.12.115 to ≤ 6.12.*; unaffected: 6.18.59 to ≤ 6.18.*; unaffected: 7.2.13 to ≤ 7.2.*; unaffected: 7.3 to ≤ * | See vendor advisory |
Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.
Is it being exploited?
This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.
How to respond
- Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
- Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
- Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.
Sources and remediation references
- https://www.cve.org/CVERecord?id=CVE-2026-99247
- https://git.kernel.org/stable/c/e8665e884e076d894f3eed8b9ea28e37a6448604
- https://git.kernel.org/stable/c/e8cfcd7e60eaa3b0dea4d71c64499604e7081736
- https://git.kernel.org/stable/c/afd38b10b1c6a5c5d6952b15b990596dab9684e6
- https://git.kernel.org/stable/c/813e18881c6472eb229a63180ff42c808e3e949b
- https://git.kernel.org/stable/c/7539c61f522ff693d9565a0411386c2236e776cd
- https://git.kernel.org/stable/c/b3b974008388ab59e44d764ba7a63c988fec2524