{"id":"CVE-2026-64579","state":"PUBLISHED","title":"xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert","description":"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 <\nthreshold and preallocates for the rest.\n\nprefixlen < 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","publishedAt":"2026-08-05T08:09:34.346Z","updatedAt":"2026-08-19T16:29:04.594Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"e48f4c3e3df35b34be719d72d737bbeaca77cf0c","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"1cdeed9df1306f1a277e715600772640d63defa9","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"43a4d510523779891cf8eca7ffb4a086b0b5d8bf","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"d9d9cc21cc90014724a14c447e3d587be9447107","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"94c00391a5117530188334f740ce26d3f1256190","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"7acc5ed2f33608a3d83b64f50a5766843b6e2485","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"6aa3796d18a9fda953ad76a62b57bf6c145cb9ef","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"f38f8cce2f7e79775b3db7e8a5eacda04ac908e4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/xfrm/xfrm_policy.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.0","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","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":["net/xfrm/xfrm_policy.c"]}],"references":["https://git.kernel.org/stable/c/e48f4c3e3df35b34be719d72d737bbeaca77cf0c","https://git.kernel.org/stable/c/1cdeed9df1306f1a277e715600772640d63defa9","https://git.kernel.org/stable/c/43a4d510523779891cf8eca7ffb4a086b0b5d8bf","https://git.kernel.org/stable/c/d9d9cc21cc90014724a14c447e3d587be9447107","https://git.kernel.org/stable/c/94c00391a5117530188334f740ce26d3f1256190","https://git.kernel.org/stable/c/7acc5ed2f33608a3d83b64f50a5766843b6e2485","https://git.kernel.org/stable/c/6aa3796d18a9fda953ad76a62b57bf6c145cb9ef","https://git.kernel.org/stable/c/f38f8cce2f7e79775b3db7e8a5eacda04ac908e4"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64579.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64579","state":"PUBLISHED","datePublished":"2026-08-05T08:09:34.346Z","dateUpdated":"2026-08-19T16:29:04.594Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.798Z"},"containers":{"cna":{"title":"xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert","descriptions":[{"lang":"en","value":"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 <\nthreshold and preallocates for the rest.\n\nprefixlen < 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"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"e48f4c3e3df35b34be719d72d737bbeaca77cf0c","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"1cdeed9df1306f1a277e715600772640d63defa9","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"43a4d510523779891cf8eca7ffb4a086b0b5d8bf","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"d9d9cc21cc90014724a14c447e3d587be9447107","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"94c00391a5117530188334f740ce26d3f1256190","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"7acc5ed2f33608a3d83b64f50a5766843b6e2485","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"6aa3796d18a9fda953ad76a62b57bf6c145cb9ef","versionType":"git"},{"version":"24969facd704a5f0dd8e08da86bf32a9ce972bee","status":"affected","lessThan":"f38f8cce2f7e79775b3db7e8a5eacda04ac908e4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/xfrm/xfrm_policy.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.0","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","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":["net/xfrm/xfrm_policy.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e48f4c3e3df35b34be719d72d737bbeaca77cf0c"},{"url":"https://git.kernel.org/stable/c/1cdeed9df1306f1a277e715600772640d63defa9"},{"url":"https://git.kernel.org/stable/c/43a4d510523779891cf8eca7ffb4a086b0b5d8bf"},{"url":"https://git.kernel.org/stable/c/d9d9cc21cc90014724a14c447e3d587be9447107"},{"url":"https://git.kernel.org/stable/c/94c00391a5117530188334f740ce26d3f1256190"},{"url":"https://git.kernel.org/stable/c/7acc5ed2f33608a3d83b64f50a5766843b6e2485"},{"url":"https://git.kernel.org/stable/c/6aa3796d18a9fda953ad76a62b57bf6c145cb9ef"},{"url":"https://git.kernel.org/stable/c/f38f8cce2f7e79775b3db7e8a5eacda04ac908e4"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-19T16:29:04.594Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}