CVE-2026-74633
CVE CVE-2026-74633EUVD EUVD-2026-64570Published 2026-08-22T15:32:13.000Z
What the advisory describes
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: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Linux — Linux b355247df104ef6644288884afd2c08b7bf49897 <b69859204d4db3acd86c1c2dadcef0d77b451933; patch: 7.1.9; b355247df104ef6644288884afd2c08b7bf49897 <ad4e9dd5fec7a322a471ff36fb9c76214e3c6992; patch: 7.2; b355247df104ef6644288884afd2c08b7bf49897 <152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9; 6.14; patch: 6.18.45; patch: 0
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.
- Linux — Linux
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