{"api_version":"1","generated_at":"2026-08-23T14:39:13+00:00","cve":"CVE-2026-74633","urls":{"html":"https://cve.report/CVE-2026-74633","api":"https://cve.report/api/cve/CVE-2026-74633.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74633","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74633"},"summary":{"title":"tracing: Fix NULL pointer dereference in module event cache removal","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix NULL pointer dereference in module event cache removal\n\nA module-only event filter such as \":mod:foo\" is cached with a NULL\nevent_mod->match when foo has not been loaded. If a later write tries to\nremove a specific match from the same module, remove_cache_mod() passes\nthe NULL cached match to strcmp(), causing a NULL pointer dereference.\n\nThe issue can be reproduced from userspace:\n\n  echo ':mod:trace_events_kunit_missing' > /sys/kernel/tracing/set_event\n  echo '!foo_bar:mod:trace_events_kunit_missing' >> /sys/kernel/tracing/set_event\n\nThe second write must be a concatenation (\">>\") to not include O_TRUNC as\nthat would cause ftrace_clear_events() to clear the cached modules lines.\n\nThe crash was reproduced on x86_64 QEMU while KUnit workers contended on\nthe event tracing path:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  #PF: supervisor read access in kernel mode\n  RIP: 0010:strcmp+0x10/0x30\n  Call Trace:\n   __ftrace_set_clr_event_nolock+0x373/0x4a0\n   ftrace_set_clr_event+0xf0/0x180\n   ftrace_event_write+0xdf/0x110\n   vfs_write+0xf6/0x440\n   ksys_write+0x68/0xe0\n   do_syscall_64+0xf9/0x540\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nCheck event_mod->match before comparing it, consistent with the existing\nNULL checks for the cached system and event fields. The mismatched removal\ncontinues to return -EINVAL; a broad cached module filter is removed with\n\"!:mod:<module>\".","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-22 16:16:36","updated_at":"2026-08-22 16:16:36"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/b69859204d4db3acd86c1c2dadcef0d77b451933","name":"https://git.kernel.org/stable/c/b69859204d4db3acd86c1c2dadcef0d77b451933","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9","name":"https://git.kernel.org/stable/c/152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ad4e9dd5fec7a322a471ff36fb9c76214e3c6992","name":"https://git.kernel.org/stable/c/ad4e9dd5fec7a322a471ff36fb9c76214e3c6992","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74633","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74633","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b355247df104ef6644288884afd2c08b7bf49897 152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b355247df104ef6644288884afd2c08b7bf49897 ad4e9dd5fec7a322a471ff36fb9c76214e3c6992 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b355247df104ef6644288884afd2c08b7bf49897 b69859204d4db3acd86c1c2dadcef0d77b451933 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.45 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.9 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/trace/trace_events.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9","status":"affected","version":"b355247df104ef6644288884afd2c08b7bf49897","versionType":"git"},{"lessThan":"ad4e9dd5fec7a322a471ff36fb9c76214e3c6992","status":"affected","version":"b355247df104ef6644288884afd2c08b7bf49897","versionType":"git"},{"lessThan":"b69859204d4db3acd86c1c2dadcef0d77b451933","status":"affected","version":"b355247df104ef6644288884afd2c08b7bf49897","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/trace/trace_events.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.14"},{"lessThan":"6.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.45","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.45","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.9","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix NULL pointer dereference in module event cache removal\n\nA module-only event filter such as \":mod:foo\" is cached with a NULL\nevent_mod->match when foo has not been loaded. If a later write tries to\nremove a specific match from the same module, remove_cache_mod() passes\nthe NULL cached match to strcmp(), causing a NULL pointer dereference.\n\nThe issue can be reproduced from userspace:\n\n  echo ':mod:trace_events_kunit_missing' > /sys/kernel/tracing/set_event\n  echo '!foo_bar:mod:trace_events_kunit_missing' >> /sys/kernel/tracing/set_event\n\nThe second write must be a concatenation (\">>\") to not include O_TRUNC as\nthat would cause ftrace_clear_events() to clear the cached modules lines.\n\nThe crash was reproduced on x86_64 QEMU while KUnit workers contended on\nthe event tracing path:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  #PF: supervisor read access in kernel mode\n  RIP: 0010:strcmp+0x10/0x30\n  Call Trace:\n   __ftrace_set_clr_event_nolock+0x373/0x4a0\n   ftrace_set_clr_event+0xf0/0x180\n   ftrace_event_write+0xdf/0x110\n   vfs_write+0xf6/0x440\n   ksys_write+0x68/0xe0\n   do_syscall_64+0xf9/0x540\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nCheck event_mod->match before comparing it, consistent with the existing\nNULL checks for the cached system and event fields. The mismatched removal\ncontinues to return -EINVAL; a broad cached module filter is removed with\n\"!:mod:<module>\"."}],"providerMetadata":{"dateUpdated":"2026-08-22T15:32:13.808Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9"},{"url":"https://git.kernel.org/stable/c/ad4e9dd5fec7a322a471ff36fb9c76214e3c6992"},{"url":"https://git.kernel.org/stable/c/b69859204d4db3acd86c1c2dadcef0d77b451933"}],"title":"tracing: Fix NULL pointer dereference in module event cache removal","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74633","datePublished":"2026-08-22T15:32:13.808Z","dateReserved":"2026-08-15T05:44:03.922Z","dateUpdated":"2026-08-22T15:32:13.808Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-22 16:16:36","lastModifiedDate":"2026-08-22 16:16:36","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74633","Ordinal":"1","Title":"tracing: Fix NULL pointer dereference in module event cache remo","CVE":"CVE-2026-74633","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74633","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix NULL pointer dereference in module event cache removal\n\nA module-only event filter such as \":mod:foo\" is cached with a NULL\nevent_mod->match when foo has not been loaded. If a later write tries to\nremove a specific match from the same module, remove_cache_mod() passes\nthe NULL cached match to strcmp(), causing a NULL pointer dereference.\n\nThe issue can be reproduced from userspace:\n\n  echo ':mod:trace_events_kunit_missing' > /sys/kernel/tracing/set_event\n  echo '!foo_bar:mod:trace_events_kunit_missing' >> /sys/kernel/tracing/set_event\n\nThe second write must be a concatenation (\">>\") to not include O_TRUNC as\nthat would cause ftrace_clear_events() to clear the cached modules lines.\n\nThe crash was reproduced on x86_64 QEMU while KUnit workers contended on\nthe event tracing path:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  #PF: supervisor read access in kernel mode\n  RIP: 0010:strcmp+0x10/0x30\n  Call Trace:\n   __ftrace_set_clr_event_nolock+0x373/0x4a0\n   ftrace_set_clr_event+0xf0/0x180\n   ftrace_event_write+0xdf/0x110\n   vfs_write+0xf6/0x440\n   ksys_write+0x68/0xe0\n   do_syscall_64+0xf9/0x540\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nCheck event_mod->match before comparing it, consistent with the existing\nNULL checks for the cached system and event fields. The mismatched removal\ncontinues to return -EINVAL; a broad cached module filter is removed with\n\"!:mod:<module>\".","Type":"Description","Title":"tracing: Fix NULL pointer dereference in module event cache remo"}]}}}