{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74363", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.887Z", "datePublished": "2026-08-15T05:58:46.220Z", "dateUpdated": "2026-08-17T05:46:21.981Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:46:21.981Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: fix UAF by restoring RCU-delayed inode freeing in bpffs\n\ncommit 4f375ade6aa9 (\"bpf: Avoid RCU context warning when unpinning\nhtab with internal structs\") moved inode cleanup from ->free_inode()\ninto ->destroy_inode() to avoid sleeping in RCU context when calling\nbpf_any_put(). However this removed the RCU delay on freeing the\ninode itself and the cached symlink body (i_link), both of which\ncan be accessed by RCU pathwalk (pick_link, may_lookup etc.).\n\nThis causes a use-after-free when a concurrent unlinkat() drops the\nlast inode reference and destroy_inode() frees the inode immediately,\nwhile another task is still walking the path in RCU mode and reads\ninode->i_opflags (offset +2) inside current_time() -> is_mgtime().\n\nKASAN reports:\n BUG: KASAN: slab-use-after-free in is_mgtime include/linux/fs.h:2313\n Read of size 2 at addr ffff8880407e4282 (offset +2 = i_opflags)\n\nThe rules (per Al Viro):\n ->destroy_inode() called immediately, can sleep, use for blocking\n cleanup e.g. bpf_any_put()\n ->free_inode() called after RCU grace period, use for freeing\n inode and anything RCU-accessible e.g. i_link\n\nFix: split the two concerns properly:\n - keep bpf_any_put() in bpf_destroy_inode() since it is blocking\n and needs to run promptly\n - introduce bpf_free_inode() to handle kfree(i_link) and\n free_inode_nonrcu() with proper RCU delay, preventing the UAF" } ], "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 triggered through local VFS and bpf(2) syscalls on bpffs (unlinkat/symlinkat/openat/stat and BPF_OBJ_GET/BPF_OBJ_PIN) racing RCU pathwalk; BPF/bpffs is not reachable from remote network services.\nAC:L - Exploitation requires a race between unlinkat dropping the last bpffs inode reference and concurrent RCU pathwalk, but the attacker controls both sides with parallel threads/syscalls and syzbot reliably reproduces the UAF without external timing.\nPR:L - Any local user with write access to a bpffs mount (default sticky world-writable /sys/fs/bpf) can create symlinks or pin/unpin BPF objects without init-namespace root, including via unprivileged BPF or delegated bpffs mounts in user namespaces.\nUI:N - No victim action is required; the attacker programmatically races their own unlink/pathwalk operations on bpffs objects they can create and remove.\nS:U - This is a kernel heap use-after-free in bpffs inode lifetime management, enabling local privilege escalation within the same security domain rather than crossing VM, IOMMU, or sandbox boundaries.\nC:H - KASAN confirmed slab use-after-free reading freed inode->i_opflags during RCU pathwalk; UAF of struct inode enables subsequent arbitrary kernel memory disclosure via heap reuse.\nI:H - Premature inode freeing permits attacker-controlled heap reuse and spraying, providing a standard kernel UAF path to arbitrary write and potential code execution beyond the initial 2-byte read.\nA:H - Concurrent RCU pathwalk of a prematurely freed bpffs inode triggers KASAN slab-UAF and kernel oops; repeated triggering can panic the system or cause denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/inode.c" ], "versions": [ { "version": "e28616ca3d67e745ecb2f10eba4a626e1fc9a203", "lessThan": "ea1c243c39e32b7fc1c2edfe32081ff7e30a877c", "status": "affected", "versionType": "git" }, { "version": "743a620c661994c7f0938e6dd32fb0883fb1e0ea", "lessThan": "5fecb71c10c28aef276ba49c718dc961745fdcf0", "status": "affected", "versionType": "git" }, { "version": "b6e9645be9eb93f7aff3ca887f8edb6f1d63358f", "lessThan": "c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2", "status": "affected", "versionType": "git" }, { "version": "ee04cff9ed4d6bb25802f5cecfcd0750500410f3", "lessThan": "53649846e0437d1d9b7cb993cfe54c367addf7ae", "status": "affected", "versionType": "git" }, { "version": "4f375ade6aa9f37fd72d7a78682f639772089eed", "lessThan": "61f19729728243c82476dee31315143ed3275e7f", "status": "affected", "versionType": "git" }, { "version": "4f375ade6aa9f37fd72d7a78682f639772089eed", "lessThan": "0497ff765746d9b2d17445c8f7cc737b36c0152a", "status": "affected", "versionType": "git" }, { "version": "4f375ade6aa9f37fd72d7a78682f639772089eed", "lessThan": "b93c55b4932dd7e32dca8cf34a3443cc87a02906", "status": "affected", "versionType": "git" }, { "version": "de2d2baecc84cc7fca52eec2b9b55d89c93e3565", "status": "affected", "versionType": "git" }, { "version": "5.15.195", "lessThan": "5.15.212", "status": "affected", "versionType": "semver" }, { "version": "6.1.157", "lessThan": "6.1.178", "status": "affected", "versionType": "semver" }, { "version": "6.6.113", "lessThan": "6.6.145", "status": "affected", "versionType": "semver" }, { "version": "6.12.54", "lessThan": "6.12.97", "status": "affected", "versionType": "semver" }, { "version": "6.17.4", "lessThan": "6.18", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/inode.c" ], "versions": [ { "version": "6.18", "status": "affected" }, { "version": "0", "lessThan": "6.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.195", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.157", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.113", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.54", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ea1c243c39e32b7fc1c2edfe32081ff7e30a877c" }, { "url": "https://git.kernel.org/stable/c/5fecb71c10c28aef276ba49c718dc961745fdcf0" }, { "url": "https://git.kernel.org/stable/c/c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2" }, { "url": "https://git.kernel.org/stable/c/53649846e0437d1d9b7cb993cfe54c367addf7ae" }, { "url": "https://git.kernel.org/stable/c/61f19729728243c82476dee31315143ed3275e7f" }, { "url": "https://git.kernel.org/stable/c/0497ff765746d9b2d17445c8f7cc737b36c0152a" }, { "url": "https://git.kernel.org/stable/c/b93c55b4932dd7e32dca8cf34a3443cc87a02906" } ], "title": "bpf: fix UAF by restoring RCU-delayed inode freeing in bpffs", "x_generator": { 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