---
cve: "CVE-2026-74636"
severity: "LOW"
cvss: 3.1
epss: "5.7%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-08-22 16:16:36"
tags: [cve, security, low]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T07:26:19+02:00"
---

# CVE-2026-74636

> 3.1 LOW

## Beschreibung

In the Linux kernel, the following vulnerability has been resolved:

tracing: Fix race between update_event_fields and, event_define_fields

The following sequence may leads race between event_define_fields()
and update_event_fields():

 CPU0 (loads module A)                      CPU1 (loads module B)
 ===============================            ===============================
 load_module(A)                             load_module(B)
   notifier_call_chain                        notifier_call_chain
     trace_module_notify                        trace_module_notify
       mutex_lock(&event_mutex)                   trace_event_update_all()
         trace_module_add_events(A)                 down_write(&trace_event_sem)
            __register_event(call_A)
              __add_event_to_tracers(call_A)
                event_define_fields(call_A)
                  for each f:                         list_for_each_entry(field,
                    list_add(&f->link,                                    &class->fields, link)
                             &class->fields)            field = class->fields->next;

Where access to the class->fields is not protected by the event_mutex in
trace_event_update_all().

This produces the following panic:
   Unable to handle kernel access ... at virtual address 0000000000000018
   pc : update_event_fields+0xf8/0x368
   Call trace:
    update_event_fields+0xf8/0x368
    trace_event_update_all+0x7c/0x2b4
    trace_module_notify+0x4c/0x1dc
    notifier_call_chain+0x84/0x168
    blocking_notifier_call_chain_robust+0x64/0xd4
    load_module+0x10c8/0x123c
    __arm64_sys_finit_module+0x230/0x31c

Fix by taking event_mutex in trace_event_update_all() before
trace_event_sem.

## Patch verfügbar (OSV)

- Kernel ≥ 5.15.216
- Kernel ≥ 6.1.183
- Kernel ≥ 6.6.152
- Kernel ≥ 6.12.104
- Kernel ≥ 6.18.45
- Kernel ≥ 7.1.9

## Referenzen

- <https://git.kernel.org/stable/c/4e39f7b4d9d36508c53e89e6cbc640728df870b5>
- <https://git.kernel.org/stable/c/a30d421468300b1e7b2f233136aeb2db8013f555>
- <https://git.kernel.org/stable/c/c3730b8373bb5059d735509b9e6a00d7eb337d7c>
- <https://git.kernel.org/stable/c/e5f1d301b4bdaa4206db251fdc691f623162b0a8>
- <https://git.kernel.org/stable/c/ed49684e69f846bf50b5050651ccdb87cfd152c0>
- <https://git.kernel.org/stable/c/f128740f39ab28d1f4ad5bdd10f3e117eec0c374>
- <https://git.kernel.org/stable/c/fdeb190b0905a6aaed1e5d6adfb8613214748d7d>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-74636) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_