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>".

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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>". (CVE-2026-74633)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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>.
    (CVE-2026-74633)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
471414	Google: sys-kernel/cchost-kernel-6_18, sys-kernel/csql-kernel-6_18, sys-kernel/lakitu-kernel-6_18, sys-kernel/lakitu-nc-kernel-6_18: security update to 20085.0.0	Tenable Cloud Security	Google COS Security Checks	Local	medium
471414	Google: sys-kernel/cchost-kernel-6_18, sys-kernel/csql-kernel-6_18, sys-kernel/lakitu-kernel-6_18, sys-kernel/lakitu-nc-kernel-6_18: security update to 20085.0.0	Tenable Self-Hosted Container Security	Google COS Security Checks	Local	medium
470389	Google: sys-kernel/cchost-kernel-6_18, sys-kernel/csql-kernel-6_18, sys-kernel/lakitu-kernel-6_18, sys-kernel/lakitu-nc-kernel-6_18: security update to 19999.44.28	Tenable Cloud Security	Google COS Security Checks	Local	medium
470389	Google: sys-kernel/cchost-kernel-6_18, sys-kernel/csql-kernel-6_18, sys-kernel/lakitu-kernel-6_18, sys-kernel/lakitu-nc-kernel-6_18: security update to 19999.44.28	Tenable Self-Hosted Container Security	Google COS Security Checks	Local	medium
351016	Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-3139)	Nessus	Amazon Linux Local Security Checks	Local	critical
338961	Linux Distros Unpatched Vulnerability : CVE-2026-74633	Nessus	Misc.	Local	medium

Detections

Analytics

CVE-2026-74633

medium

Tenable Plugins

medium

medium

medium

medium

critical

medium