{"id":"CVE-2026-52973","summary":"futex: Drop CLONE_THREAD requirement for private default hash alloc","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Drop CLONE_THREAD requirement for private default hash alloc\n\nCurrently need_futex_hash_allocate_default() depends on strict pthread\nsemantics, abusing CLONE_THREAD.  This breaks the non-concurrency\nassumptions when doing the mm-\u003efutex_ref pcpu allocations, leading to\nbugs[0] when sharing the mm in other ways; ie:\n\n    BUG: KASAN: slab-use-after-free in futex_hash_put\n\n... where the +1 bias can end up on a percpu counter that mm-\u003efutex_ref\nno longer points at.\n\nLoosen the check to cover any CLONE_VM clone, except vfork().  Excluding\nvfork keeps the existing paths untouched (no overhead), and we can't\nrace in the first place: either the parent is suspended and the child\nruns alone, or mm-\u003efutex_ref is already allocated from an earlier\nCLONE_VM.","modified":"2026-07-10T03:54:53.605368525Z","published":"2026-06-24T16:28:51.171Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52973.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1dcd36420af2da5bd59306dba9caf78e3d248b1d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/974ac49a9a068b0591a59f65c63eb06579a13091"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ee9dce44362b2d8132c32964656ab6dff7dfbc6a"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52973.json"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-52973"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52973.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-52973"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2492413"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d9b05321e21e4b218de4ce8a590bf375f58b6346"},{"fixed":"1dcd36420af2da5bd59306dba9caf78e3d248b1d"},{"fixed":"974ac49a9a068b0591a59f65c63eb06579a13091"},{"fixed":"ee9dce44362b2d8132c32964656ab6dff7dfbc6a"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52973.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.18.33"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52973.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}