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CVE-2026-74633— tracing: Fix NULL pointer dereference in module event cache removal

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，已修复以下漏洞： tracing：修复模块事件缓存移除过程中的空指针解引用问题 当模块尚未加载时，仅针对模块的事件过滤器（例如 ）会被缓存，此时其 字段为 NULL。如果后续尝试从同一模块中移除特定的匹配项， 会将该 NULL 缓存的匹配项传递给 ，从而导致空指针解引用。 该问题可从用户态重现： 第二次写入必须使用追加方式（ ），而不能使用覆盖方式（ ），因为覆盖操作会引入 标志，导致 清空已缓存的模块过滤规则。 该崩溃在 x86_64 QEMU 环境中复现，当时 KUnit 测试工事件追踪

AI Predicted 6.8 Difficulty: Easy EPSS 0.21% · P11

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux b355247df104ef6644288884afd2c08b7bf49897< 152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9 affected
b355247df104ef6644288884afd2c08b7bf49897< ad4e9dd5fec7a322a471ff36fb9c76214e3c6992 affected
b355247df104ef6644288884afd2c08b7bf49897< b69859204d4db3acd86c1c2dadcef0d77b451933 affected
6.14 affected
< 6.14 unaffected
6.18.45≤ 6.18.* unaffected
7.1.9≤ 7.1.* unaffected
7.2≤ * unaffected
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I. Basic Information for CVE-2026-74633

Vulnerability Information
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Vulnerability Title
tracing: Fix NULL pointer dereference in module event cache removal
Source: CVE Program / CVE List V5
Vulnerability Description
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>".
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux b355247df104ef6644288884afd2c08b7bf49897 ~ 152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9 -
Linux Linux 6.14 -

II. Public POCs for CVE-2026-74633

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III. Intelligence Information for CVE-2026-74633

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Patches & Fixes for CVE-2026-74633 (2)

Same Patch Batch · Linux · 2026-08-22 · 150 CVEs total

CVE-2026-74640 ALSA: FCP: fix OOB write in fcp_meter_ctl_get()
CVE-2026-74621 net/sched: act_ct: fix sk_buff leak when the header checks reject a packet
CVE-2026-74622 net: atlantic: free RX pages of consumed but not refilled buffers
CVE-2026-74623 net: atlantic: free stranded TX buffers on ring deinit
CVE-2026-74624 netfilter: nf_conntrack: defer invalid log until after unlock
CVE-2026-74625 netfilter: bridge: release template ct on non-IP path
CVE-2026-74627 net: devmem: prevent net-iov / page mixing
CVE-2026-74626 NTB: ntb_netdev: Preserve RX queue depth on allocation failure
CVE-2026-74628 net/x25: fix use-after-free of the socket by its timers
CVE-2026-74629 net/dibs: Correct freeing of dmb_clientid_arr
CVE-2026-74631 net: smc: fix splice entry lifetime imbalance in smc_rx_splice
CVE-2026-74630 ipv6: prevent in6_dev_get() from resurrecting inet6_dev
CVE-2026-74632 mm/huge_memory: fix huge_zero_pfn race
CVE-2026-74634 ring-buffer: Prevent subbuf order change when resizing is disabled
CVE-2026-74635 fbdev: bitblit: bound-check glyph index in bit_cursor()
CVE-2026-74636 tracing: Fix race between update_event_fields and, event_define_fields
CVE-2026-74637 perf/core: Fix group leader use-after-free after sibling detach
CVE-2026-74639 ALSA: us144mkii: re-anchor capture URBs on resubmission
CVE-2026-74638 drm/v3d: Serialize the scheduler timeout handlers
CVE-2026-74651 staging: rtl8723bs: fix OOB read in rtw_get_wpa_ie()

Showing top 20 of 150 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-74633

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