{"id":"CVE-2026-64579","summary":"xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert\n\nxfrm_hash_rebuild()'s first loop preallocates the bins/chains the reinsert\nloop needs, so the reinsert (after hlist_del_rcu()) cannot allocate or\nfail. But its guard is inverted: it skips policies with prefixlen \u003c\nthreshold and preallocates for the rest.\n\nprefixlen \u003c threshold is exactly when policy_hash_bysel() returns NULL and\nthe reinsert takes the allocating xfrm_policy_inexact_insert() path. So the\nloop preallocates for the exact policies (which never allocate) and skips\nthe inexact ones, whose bin/node is then allocated GFP_ATOMIC during\nreinsert. On failure the error path only WARN_ONCE()s and continues,\nleaving a poisoned bydst node; the next rebuild's hlist_del_rcu()\ndereferences LIST_POISON2 and takes a GPF. Reachable under memory pressure,\ndeterministic via failslab.\n\nInvert the guard so preallocation covers exactly the reinserted policies;\nthe reinsert then allocates nothing and cannot fail.\n\nCrash:\n  Oops: general protection fault, probably for non-canonical address\n  0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI\n  KASAN: maybe wild-memory-access in range [0xdead...]\n  ...\n  Workqueue: events xfrm_hash_rebuild\n  RIP: 0010:xfrm_hash_rebuild+0x5b3/0x1190\n  RAX: dead000000000122   (LIST_POISON2 + offset)\n  ...\n  Call Trace:\n   hlist_del_rcu (include/linux/rculist.h:599)\n   xfrm_hash_rebuild (net/xfrm/xfrm_policy.c:1365)\n   process_one_work (kernel/workqueue.c:3322)\n   worker_thread (kernel/workqueue.c:3486)\n   kthread (kernel/kthread.c:436)\n   ret_from_fork (arch/x86/kernel/process.c:158)\n   ret_from_fork_asm (arch/x86/entry/entry_64.S:245)\n   ...\n  Kernel panic - not syncing: Fatal exception in interrupt","modified":"2026-08-07T03:30:46.829315907Z","published":"2026-08-05T08:09:34.346Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64579.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6aa3796d18a9fda953ad76a62b57bf6c145cb9ef"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7acc5ed2f33608a3d83b64f50a5766843b6e2485"},{"type":"WEB","url":"https://git.kernel.org/stable/c/94c00391a5117530188334f740ce26d3f1256190"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d9d9cc21cc90014724a14c447e3d587be9447107"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f38f8cce2f7e79775b3db7e8a5eacda04ac908e4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64579.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64579"},{"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":"24969facd704a5f0dd8e08da86bf32a9ce972bee"},{"fixed":"d9d9cc21cc90014724a14c447e3d587be9447107"},{"fixed":"94c00391a5117530188334f740ce26d3f1256190"},{"fixed":"7acc5ed2f33608a3d83b64f50a5766843b6e2485"},{"fixed":"6aa3796d18a9fda953ad76a62b57bf6c145cb9ef"},{"fixed":"f38f8cce2f7e79775b3db7e8a5eacda04ac908e4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64579.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0"},{"fixed":"6.6.148"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.101"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.42"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64579.json"}}],"schema_version":"1.8.0"}