Linux Kernel up to 6.18.44/7.1.8 tracing set_event remove_cache_mod null pointer dereference

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3.0$0-$5k0.87

Summaryinfo

A vulnerability marked as problematic has been reported in Linux Kernel up to 6.18.44/7.1.8. This vulnerability affects the function remove_cache_mod of the file /sys/kernel/tracing/set_event of the component tracing. Performing a manipulation results in null pointer dereference. This vulnerability is cataloged as CVE-2026-74633. The attack must be initiated from a local position. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.18.44/7.1.8. This affects the function remove_cache_mod of the file /sys/kernel/tracing/set_event of the component tracing. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix NULL pointer dereference in module event cache removal A module-only event filter such as ":mod:foo" is cached with a NULL event_mod->match when foo has not been loaded. If a later write tries to remove a specific match from the same module, remove_cache_mod() passes the NULL cached match to strcmp(), causing a NULL pointer dereference. The issue can be reproduced from userspace: echo ':mod:trace_events_kunit_missing' > /sys/kernel/tracing/set_event echo '!foo_bar:mod:trace_events_kunit_missing' >> /sys/kernel/tracing/set_event The second write must be a concatenation (">>") to not include O_TRUNC as that would cause ftrace_clear_events() to clear the cached modules lines. The crash was reproduced on x86_64 QEMU while KUnit workers contended on the event tracing path: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode RIP: 0010:strcmp+0x10/0x30 Call Trace: __ftrace_set_clr_event_nolock+0x373/0x4a0 ftrace_set_clr_event+0xf0/0x180 ftrace_event_write+0xdf/0x110 vfs_write+0xf6/0x440 ksys_write+0x68/0xe0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f Check event_mod->match before comparing it, consistent with the existing NULL checks for the cached system and event fields. The mismatched removal continues to return -EINVAL; a broad cached module filter is removed with "!:mod:<module>".

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-74633 since 08/15/2026. The exploitability is told to be easy. Attacking locally is a requirement. Additional levels of successful authentication are needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 6.18.45 or 7.1.9 eliminates this vulnerability. Applying the patch 152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9/ad4e9dd5fec7a322a471ff36fb9c76214e3c6992/b69859204d4db3acd86c1c2dadcef0d77b451933 is able to eliminate this problem.

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Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.1
VulDB Meta Temp Score: 3.0

VulDB Base Score: 3.1
VulDB Temp Score: 3.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.45/7.1.9
Patch: 152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9/ad4e9dd5fec7a322a471ff36fb9c76214e3c6992/b69859204d4db3acd86c1c2dadcef0d77b451933

Timelineinfo

08/15/2026 CVE reserved
08/22/2026 +7 days Advisory disclosed
08/22/2026 +0 days VulDB entry created
08/22/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74633 (🔒)
GCVE (CVE): GCVE-0-2026-74633
GCVE (VulDB): GCVE-100-394419

Entryinfo

Created: 08/22/2026 18:30
Changes: 08/22/2026 18:30 (60)
Complete: 🔍
Cache ID: 216::103

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