CVE-2026-74636
tracing: Fix race between update_event_fields and, event_define_fields
Description
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.
INFO
Published Date :
Aug. 22, 2026, 4:16 p.m.
Last Modified :
Aug. 22, 2026, 4:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Acquire event_mutex before trace_event_sem.
- Review and update module loading and tracing code.
- Apply the provided patch to the Linux kernel.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74636.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74636 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74636
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-74636 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74636 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 22, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7c6bd60999f32138e3b73fd97ea11ef47a94de25', 'lessThan': '4e39f7b4d9d36508c53e89e6cbc640728df870b5', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3bc8547d3be60898818885f5bf22d0a62e2eb48', 'lessThan': 'a30d421468300b1e7b2f233136aeb2db8013f555', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3bc8547d3be60898818885f5bf22d0a62e2eb48', 'lessThan': 'e5f1d301b4bdaa4206db251fdc691f623162b0a8', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3bc8547d3be60898818885f5bf22d0a62e2eb48', 'lessThan': 'fdeb190b0905a6aaed1e5d6adfb8613214748d7d', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3bc8547d3be60898818885f5bf22d0a62e2eb48', 'lessThan': 'ed49684e69f846bf50b5050651ccdb87cfd152c0', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3bc8547d3be60898818885f5bf22d0a62e2eb48', 'lessThan': 'f128740f39ab28d1f4ad5bdd10f3e117eec0c374', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3bc8547d3be60898818885f5bf22d0a62e2eb48', 'lessThan': 'c3730b8373bb5059d735509b9e6a00d7eb337d7c', 'versionType': 'git'}, {'status': 'affected', 'version': '55defdf935fab9f2989a197aae1042c082d9a343', 'versionType': 'git'}, {'status': 'affected', 'version': '0c53a5c80e6e286733381a1d9f255ba4039e2e45', 'versionType': 'git'}, {'status': 'affected', 'version': '5.15.33', 'lessThan': '5.15.216', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.16.19', 'lessThan': '5.17', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.17.2', 'lessThan': '5.18', 'versionType': 'semver'}], 'programFiles': ['kernel/trace/trace_events.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.18'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.18', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.15.216', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.183', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.152', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.104', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.45', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.9', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['kernel/trace/trace_events.c'], 'defaultStatus': 'affected'}] Added Description 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. Added Reference https://git.kernel.org/stable/c/4e39f7b4d9d36508c53e89e6cbc640728df870b5 Added Reference https://git.kernel.org/stable/c/a30d421468300b1e7b2f233136aeb2db8013f555 Added Reference https://git.kernel.org/stable/c/c3730b8373bb5059d735509b9e6a00d7eb337d7c Added Reference https://git.kernel.org/stable/c/e5f1d301b4bdaa4206db251fdc691f623162b0a8 Added Reference https://git.kernel.org/stable/c/ed49684e69f846bf50b5050651ccdb87cfd152c0 Added Reference https://git.kernel.org/stable/c/f128740f39ab28d1f4ad5bdd10f3e117eec0c374 Added Reference https://git.kernel.org/stable/c/fdeb190b0905a6aaed1e5d6adfb8613214748d7d