Unknown

CVE-2026-74636 — tracing: Fix race between update_event_fields and, event_define_fields

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.

Published Aug 22, 2026 · Updated Oct 14, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.17%

ahead of 6% of scored CVEs · Oct 14, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 7c6bd60999f32138e3b73fd97ea11ef47a94de25 and < 4e39f7b4d9d36508c53e89e6cbc640728df870b5≥ b3bc8547d3be60898818885f5bf22d0a62e2eb48 and < a30d421468300b1e7b2f233136aeb2db8013f555≥ b3bc8547d3be60898818885f5bf22d0a62e2eb48 and < e5f1d301b4bdaa4206db251fdc691f623162b0a8≥ b3bc8547d3be60898818885f5bf22d0a62e2eb48 and < fdeb190b0905a6aaed1e5d6adfb8613214748d7d≥ b3bc8547d3be60898818885f5bf22d0a62e2eb48 and < ed49684e69f846bf50b5050651ccdb87cfd152c0≥ b3bc8547d3be60898818885f5bf22d0a62e2eb48 and < f128740f39ab28d1f4ad5bdd10f3e117eec0c374≥ b3bc8547d3be60898818885f5bf22d0a62e2eb48 and < c3730b8373bb5059d735509b9e6a00d7eb337d7cversion 55defdf935fab9f2989a197aae1042c082d9a343 and 5 more version 0c53a5c80e6e286733381a1d9f255ba4039e2e45≥ 5.15.33 and < 5.15.216≥ 5.16.19 and < 5.17≥ 5.17.2 and < 5.18version 5.18	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.17%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 14, 2026
Affected products added · linux/linux
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 14, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 14, 2026 · NIST National Vulnerability Database
CVE published
Aug 22, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 14, 2026 – Oct 14, 2026
1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

9 on the record

git.kernel.org/stable/c/f128740f39ab28d1f4ad5bdd10f3e117eec0c374
NIST National Vulnerability Database
git.kernel.org/stable/c/e5f1d301b4bdaa4206db251fdc691f623162b0a8
NIST National Vulnerability Database
git.kernel.org/stable/c/c3730b8373bb5059d735509b9e6a00d7eb337d7c
NIST National Vulnerability Database
git.kernel.org/stable/c/a30d421468300b1e7b2f233136aeb2db8013f555
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2026-74636
GitHub Security Advisories
git.kernel.org/stable/c/fdeb190b0905a6aaed1e5d6adfb8613214748d7d
NIST National Vulnerability Database
github.com/advisories/GHSA-jcq2-873m-mp53
GitHub Security Advisories
git.kernel.org/stable/c/ed49684e69f846bf50b5050651ccdb87cfd152c0
NIST National Vulnerability Database
git.kernel.org/stable/c/4e39f7b4d9d36508c53e89e6cbc640728df870b5
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 13h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 13h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-74636 is "tracing: Fix race between update_event_fields and, event_define_fields", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.17% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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