{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23415", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:46.014Z", "datePublished": "2026-04-02T11:40:56.476Z", "dateUpdated": "2026-08-05T12:21:35.941Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:21:35.941Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()\n\nDuring futex_key_to_node_opt() execution, vma->vm_policy is read under\nspeculative mmap lock and RCU. Concurrently, mbind() may call\nvma_replace_policy() which frees the old mempolicy immediately via\nkmem_cache_free().\n\nThis creates a race where __futex_key_to_node() dereferences a freed\nmempolicy pointer, causing a use-after-free read of mpol->mode.\n\n[ 151.412631] BUG: KASAN: slab-use-after-free in __futex_key_to_node (kernel/futex/core.c:349)\n[ 151.414046] Read of size 2 at addr ffff888001c49634 by task e/87\n\n[ 151.415969] Call Trace:\n\n[ 151.416732] __asan_load2 (mm/kasan/generic.c:271)\n[ 151.416777] __futex_key_to_node (kernel/futex/core.c:349)\n[ 151.416822] get_futex_key (kernel/futex/core.c:374 kernel/futex/core.c:386 kernel/futex/core.c:593)\n\nFix by adding rcu to __mpol_put()." } ], "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 vulnerable path is reached through local futex2/io_uring futex operations using FUTEX2_MPOL against the caller's user address space. It is not exposed directly to remote packets or adjacent/physical inputs.\nAC:L - The attacker can control both sides of the race by running concurrent threads that invoke futex wake/wait key derivation and mbind()/set_mempolicy_home_node() policy replacement on the same VMA. No external victim timing or rare state is required once the affected CONFIG_FUTEX_MPOL kernel is in use.\nPR:L - Both futex operations and basic mbind() VMA policy replacement are available to an unprivileged local user for their own process address space. The only relevant capability check is for MPOL_MF_MOVE_ALL, which is not needed to replace the VMA policy and trigger the UAF.\nUI:N - No victim action is required; the attacker can create the mapping, set policy, and issue the racing syscalls directly. Exploitation is self-contained in attacker-controlled local processes/threads.\nS:U - The bug is in the kernel's futex/mempolicy handling and affects the same kernel security authority. This is a standard local kernel vulnerability rather than a VM/IOMMU or separate-scope boundary crossing.\nC:H - This is a kernel use-after-free of struct mempolicy during futex key derivation, and UAF conditions can expose freed kernel heap contents or be shaped with heap reuse. Following the higher-severity rule for UAFs, confidentiality impact is High.\nI:H - The stale mempolicy data influences futex hash node selection and subsequent kernel data structure access, making memory corruption or control-flow-relevant exploitation defensible under UAF heap reuse. Following the higher-severity rule for UAFs, integrity impact is High.\nA:H - The reported failure is a KASAN slab-use-after-free in __futex_key_to_node(), and stale or invalid policy data can crash/oops the kernel. A local attacker can trigger the race repeatedly, so availability impact is High." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/mempolicy.h", "kernel/futex/core.c", "mm/mempolicy.c" ], "versions": [ { "version": "c042c505210dc3453f378df432c10fff3d471bc5", "lessThan": "853f70c67d1b37e368fdcb3e328c4b8c04f53ac0", "status": "affected", "versionType": "git" }, { "version": "c042c505210dc3453f378df432c10fff3d471bc5", "lessThan": "7e196194ea27bd49adf3551e2aceb83498eb73fe", "status": "affected", "versionType": "git" }, { "version": "c042c505210dc3453f378df432c10fff3d471bc5", "lessThan": "190a8c48ff623c3d67cb295b4536a660db2012aa", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/mempolicy.h", "kernel/futex/core.c", "mm/mempolicy.c" ], "versions": [ { "version": "6.16", "status": "affected" }, { "version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.21", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.11", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "6.16", "versionEndExcluding": "6.18.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.19.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/853f70c67d1b37e368fdcb3e328c4b8c04f53ac0" }, { "url": "https://git.kernel.org/stable/c/7e196194ea27bd49adf3551e2aceb83498eb73fe" }, { "url": "https://git.kernel.org/stable/c/190a8c48ff623c3d67cb295b4536a660db2012aa" } ], "title": "futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()", "x_generator": { "engine": "bippy-1.2.0" } } } }