{"id":"CVE-2026-74605","state":"PUBLISHED","title":"eventfs: Use children field for rcu head and add memory barriers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\neventfs: Use children field for rcu head and add memory barriers\n\nWhen an eventfs inode is freed, it sets ei->is_freed and then uses its\nei->list to add it to the srcu link list as the list field is a union with\nthe rcu list head. As the ei->list is used to iterate over an SRCU\nprotected list without taking the eventfs_mutex, there's nothing stopping\nthe iteration over that list to see the ei->rcu instead of the ei->list\nand it will read a corrupt target.\n\nTo fix this, change the union of the rcu list head with the children list.\nOn freeing the eventfs inode, set the is_free and execute a smp_wmb()\nbefore adding the eventfs inode to the SRCU list.\n\nOn iteration of the ei->children list, at the start, execute a smp_rmb()\nand then read the is_freed of the ei to see if the children list is still\nvalid. If is_freed is set, then the ei_child read is not valid and the\nloop should exit immediately.","publishedAt":"2026-08-22T15:31:53.063Z","updatedAt":"2026-10-21T12:46:03.903Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f3f41f444b321ec393edbc251e024fd62658ce55","status":"affected","lessThan":"25d27d5fa8645ab61018c3efec5c69f49280ca7d","versionType":"git"},{"version":"704f960dbee2f1634f4b4e16f208cb16eaf41c1e","status":"affected","lessThan":"1b95382da85cff3bf0f922ff0275f186abdadfce","versionType":"git"},{"version":"704f960dbee2f1634f4b4e16f208cb16eaf41c1e","status":"affected","lessThan":"2b80707b9e27671e10840d17c6f8f774c4ad9847","versionType":"git"},{"version":"704f960dbee2f1634f4b4e16f208cb16eaf41c1e","status":"affected","lessThan":"004f7232e49730448f91665e76bdd7dff8e0c638","versionType":"git"},{"version":"704f960dbee2f1634f4b4e16f208cb16eaf41c1e","status":"affected","lessThan":"f0ece16ffca7384787b692431961ce202907acf5","versionType":"git"},{"version":"305c4e4d80aca2c2d9cf2ebdea56e2eca6d3a6aa","status":"affected","versionType":"git"},{"version":"6.6.18","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.7.6","status":"affected","lessThan":"6.8","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/tracefs/event_inode.c","fs/tracefs/internal.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.9","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/tracefs/event_inode.c","fs/tracefs/internal.h"]}],"references":["https://git.kernel.org/stable/c/25d27d5fa8645ab61018c3efec5c69f49280ca7d","https://git.kernel.org/stable/c/1b95382da85cff3bf0f922ff0275f186abdadfce","https://git.kernel.org/stable/c/2b80707b9e27671e10840d17c6f8f774c4ad9847","https://git.kernel.org/stable/c/004f7232e49730448f91665e76bdd7dff8e0c638","https://git.kernel.org/stable/c/f0ece16ffca7384787b692431961ce202907acf5"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74605.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74605","state":"PUBLISHED","datePublished":"2026-08-22T15:31:53.063Z","dateUpdated":"2026-10-21T12:46:03.903Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.919Z"},"containers":{"cna":{"title":"eventfs: Use children field for rcu head and add memory barriers","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\neventfs: Use children field for rcu head and add memory barriers\n\nWhen an eventfs inode is freed, it sets ei->is_freed and then uses its\nei->list to add it to the srcu link list as the list field is a union with\nthe rcu list head. As the ei->list is used to iterate over an SRCU\nprotected list without taking the eventfs_mutex, there's nothing stopping\nthe iteration over that list to see the ei->rcu instead of the ei->list\nand it will read a corrupt target.\n\nTo fix this, change the union of the rcu list head with the children list.\nOn freeing the eventfs inode, set the is_free and execute a smp_wmb()\nbefore adding the eventfs inode to the SRCU list.\n\nOn iteration of the ei->children list, at the start, execute a smp_rmb()\nand then read the is_freed of the ei to see if the children list is still\nvalid. If is_freed is set, then the ei_child read is not valid and the\nloop should exit immediately."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f3f41f444b321ec393edbc251e024fd62658ce55","status":"affected","lessThan":"25d27d5fa8645ab61018c3efec5c69f49280ca7d","versionType":"git"},{"version":"704f960dbee2f1634f4b4e16f208cb16eaf41c1e","status":"affected","lessThan":"1b95382da85cff3bf0f922ff0275f186abdadfce","versionType":"git"},{"version":"704f960dbee2f1634f4b4e16f208cb16eaf41c1e","status":"affected","lessThan":"2b80707b9e27671e10840d17c6f8f774c4ad9847","versionType":"git"},{"version":"704f960dbee2f1634f4b4e16f208cb16eaf41c1e","status":"affected","lessThan":"004f7232e49730448f91665e76bdd7dff8e0c638","versionType":"git"},{"version":"704f960dbee2f1634f4b4e16f208cb16eaf41c1e","status":"affected","lessThan":"f0ece16ffca7384787b692431961ce202907acf5","versionType":"git"},{"version":"305c4e4d80aca2c2d9cf2ebdea56e2eca6d3a6aa","status":"affected","versionType":"git"},{"version":"6.6.18","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.7.6","status":"affected","lessThan":"6.8","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/tracefs/event_inode.c","fs/tracefs/internal.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.9","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/tracefs/event_inode.c","fs/tracefs/internal.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/25d27d5fa8645ab61018c3efec5c69f49280ca7d"},{"url":"https://git.kernel.org/stable/c/1b95382da85cff3bf0f922ff0275f186abdadfce"},{"url":"https://git.kernel.org/stable/c/2b80707b9e27671e10840d17c6f8f774c4ad9847"},{"url":"https://git.kernel.org/stable/c/004f7232e49730448f91665e76bdd7dff8e0c638"},{"url":"https://git.kernel.org/stable/c/f0ece16ffca7384787b692431961ce202907acf5"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only via local syscalls (getdents64/readdir on tracefs eventfs directories through eventfs_iterate); tracefs is a kernel pseudo-filesystem under /sys/kernel/tracing with no network, adjacent-wireless, or physical-device entry path.\nAC:L - A single multithreaded attacker can loop getdents on events/ or events/kprobes/ while concurrently adding/removing kprobes via kprobe_events writes that call eventfs_remove_dir; the attacker controls both the SRCU list walk and the free path, making the race reliably triggerable.\nPR:L - Exploitation needs only local tracefs read/write access (getdents plus kprobe_events to create/remove eventfs children); kprobe_events checks only LOCKDOWN_TRACEFS and DAC with no capable(), and tracing-group gid mounts, Android/ChromeOS, and developer systems commonly grant this to unprivileged users.\nUI:N - The attacker performs all concurrent directory reads and dynamic event removals in their own process; no separate victim mount, click, or configuration action is required beyond tracefs already being accessible on the system.\nS:U - The union misuse causes kernel heap/list corruption and use-after-free within the tracing filesystem subsystem on the same host; it does not cross VM, container, IOMMU, or other security boundaries to affect a different authority.\nC:H - During list_for_each_entry_srcu over ei->children, a concurrently freed child repurposes ei->list (union with rcu_head) for SRCU teardown, so the iterator follows corrupt list pointers and dereferences freed or attacker-influenced kernel memory typical of UAF read primitives.\nI:H - Corrupt SRCU list traversal over freed eventfs_inode objects is classic kernel UAF memory corruption that can be combined with heap grooming from repeated kprobe create/delete to obtain arbitrary kernel writes and local privilege escalation, not merely a bounded crash.\nA:H - Following a child's list.next after the list/rcu union is switched during free_ei() readily causes invalid pointer dereferences, kernel oops, or panic; the race can be retriggered at will by alternating getdents with dynamic event teardown."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:46:03.903Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.18","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.1.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7.6"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}