{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64436","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T15:36:31.787Z","datePublished":"2026-07-25T08:51:10.370Z","dateUpdated":"2026-08-17T04:55:37.549Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T04:55:37.549Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: af_key: initialize alg_key_len for IPComp states\n\npfkey_msg2xfrm_state() handles the IPComp (SADB_X_SATYPE_IPCOMP) case by\nallocating x->calg and copying only the algorithm name:\n\n\tx->calg = kmalloc_obj(*x->calg);\n\tif (!x->calg) {\n\t\terr = -ENOMEM;\n\t\tgoto out;\n\t}\n\tstrcpy(x->calg->alg_name, a->name);\n\tx->props.calgo = sa->sadb_sa_encrypt;\n\nUnlike the authentication (x->aalg) and encryption (x->ealg) branches of\nthe same function, the compression branch never initializes\ncalg->alg_key_len.  IPComp carries no key and the allocation only\nreserves sizeof(struct xfrm_algo) (i.e. no room for a key), so the field\nis left containing uninitialized slab data.\n\ncalg->alg_key_len is later used as a length by xfrm_algo_clone() when an\nIPComp state is cloned during XFRM_MSG_MIGRATE:\n\n\txfrm_state_migrate()\n\t  xfrm_state_clone_and_setup()\n\t    x->calg = xfrm_algo_clone(orig->calg);\n\t      kmemdup(orig, xfrm_alg_len(orig));\n\nwhere xfrm_alg_len() returns sizeof(*alg) + (alg_key_len + 7) / 8.  With\na non-zero garbage alg_key_len, kmemdup() reads past the end of the\n68-byte calg object.  Adding an IPComp SA via PF_KEY and then migrating\nit triggers (net-next, KASAN, init_on_alloc=0):\n\n  BUG: KASAN: slab-out-of-bounds in kmemdup_noprof+0x44/0x60\n  Read of size 4164 at addr ff11000025a74980 by task diag2/9287\n  CPU: 3 UID: 0 PID: 9287 Comm: diag2 7.1.0-rc6-g903db046d557 #1\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x10e/0x1f0\n   print_report+0xf7/0x600\n   kasan_report+0xe4/0x120\n   kasan_check_range+0x105/0x1b0\n   __asan_memcpy+0x23/0x60\n   kmemdup_noprof+0x44/0x60\n   xfrm_state_migrate+0x70a/0x1da0\n   xfrm_migrate+0x753/0x18a0\n   xfrm_do_migrate+0xb47/0xf10\n   xfrm_user_rcv_msg+0x411/0xb50\n   netlink_rcv_skb+0x158/0x420\n   xfrm_netlink_rcv+0x71/0x90\n   netlink_unicast+0x584/0x850\n   netlink_sendmsg+0x8b0/0xdc0\n   ____sys_sendmsg+0x9f7/0xb90\n   ___sys_sendmsg+0x134/0x1d0\n   __sys_sendmsg+0x16d/0x220\n   do_syscall_64+0x116/0x7d0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   </TASK>\n\n  Allocated by task 9287:\n   kasan_save_stack+0x33/0x60\n   kasan_save_track+0x14/0x30\n   __kasan_kmalloc+0xaa/0xb0\n   pfkey_add+0x2652/0x2ea0\n   pfkey_process+0x6d0/0x830\n   pfkey_sendmsg+0x42c/0x850\n   __sys_sendto+0x461/0x4b0\n   __x64_sys_sendto+0xe0/0x1c0\n   do_syscall_64+0x116/0x7d0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n  The buggy address belongs to the object at ff11000025a74980\n   which belongs to the cache kmalloc-96 of size 96\n  The buggy address is located 0 bytes inside of\n   allocated 68-byte region [ff11000025a74980, ff11000025a749c4)\n\nDepending on the uninitialized value the same field can instead request\nan oversized kmemdup() allocation and make the migration clone fail.\n\nThe XFRM netlink path is not affected: verify_one_alg() rejects an\nXFRMA_ALG_COMP attribute shorter than xfrm_alg_len(), so a calg added via\nXFRM_MSG_NEWSA is always self-consistent.\n\nInitialize calg->alg_key_len to 0, matching the aalg/ealg branches."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires local PF_KEY and XFRM netlink messages; received IPComp network packets cannot create or migrate the vulnerable state.\nAC:L - The attacker can deterministically prime the same kmalloc-96 cache and control the stale length before triggering migration. No race or victim-controlled condition is required.\nPR:L - Both paths require CAP_NET_ADMIN relative to the network namespace's owning user namespace. An unprivileged user can obtain this capability in a newly created user and network namespace.\nUI:N - No victim action is required after the attacker gains local execution and submits the crafted state and migration messages.\nS:U - The vulnerability affects the host kernel within its existing security authority and does not cross a VM, IOMMU, or equivalent scope boundary.\nC:H - The controlled length causes a potentially large out-of-bounds read across adjacent kernel heap objects, which can capture sensitive kernel memory and is not tightly bounded.\nI:N - kmemdup allocates a destination matching the computed length, and the vulnerable operation only over-reads the source. No out-of-bounds write or control-flow modification path was identified.\nA:H - The over-read can trigger a kernel fault or panic under memory-safety enforcement. Controlled oversized clone allocations can also be repeated across states to exhaust kernel memory."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/key/af_key.c"],"versions":[{"version":"80c9abaabf4283f7cf4a0b3597cd302506635b7f","lessThan":"58e82fc3dedb57b1432292504415b224fd2d6acb","status":"affected","versionType":"git"},{"version":"80c9abaabf4283f7cf4a0b3597cd302506635b7f","lessThan":"01b9115b55018123ef2449ac4951f89147a8428e","status":"affected","versionType":"git"},{"version":"80c9abaabf4283f7cf4a0b3597cd302506635b7f","lessThan":"3f63d1752d90c0e28be931a48ab5d89bc97d637d","status":"affected","versionType":"git"},{"version":"80c9abaabf4283f7cf4a0b3597cd302506635b7f","lessThan":"273c06b81d2e902b21acc801ae18c8276c8a9b69","status":"affected","versionType":"git"},{"version":"80c9abaabf4283f7cf4a0b3597cd302506635b7f","lessThan":"6de2a650917bedaaefd65b17cede83c5e2c1dedd","status":"affected","versionType":"git"},{"version":"80c9abaabf4283f7cf4a0b3597cd302506635b7f","lessThan":"e8417353cbd078d10531ba3928e609c84ab09e6b","status":"affected","versionType":"git"},{"version":"80c9abaabf4283f7cf4a0b3597cd302506635b7f","lessThan":"cea34abc94b0a81e3a8b5cfb41cf45af37c2c67e","status":"affected","versionType":"git"},{"version":"80c9abaabf4283f7cf4a0b3597cd302506635b7f","lessThan":"d129c3177d7b1138fd5066fcc63a698b3ba415b0","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/key/af_key.c"],"versions":[{"version":"2.6.21","status":"affected"},{"version":"0","lessThan":"2.6.21","status":"unaffected","versionType":"semver"},{"version":"5.10.261","lessThanOrEqual":"5.10.*","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":"6.12.96","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.39","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.4","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":"2.6.21","versionEndExcluding":"5.10.261"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.21","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.21","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.21","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.21","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.21","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.21","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.21","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/58e82fc3dedb57b1432292504415b224fd2d6acb"},{"url":"https://git.kernel.org/stable/c/01b9115b55018123ef2449ac4951f89147a8428e"},{"url":"https://git.kernel.org/stable/c/3f63d1752d90c0e28be931a48ab5d89bc97d637d"},{"url":"https://git.kernel.org/stable/c/273c06b81d2e902b21acc801ae18c8276c8a9b69"},{"url":"https://git.kernel.org/stable/c/6de2a650917bedaaefd65b17cede83c5e2c1dedd"},{"url":"https://git.kernel.org/stable/c/e8417353cbd078d10531ba3928e609c84ab09e6b"},{"url":"https://git.kernel.org/stable/c/cea34abc94b0a81e3a8b5cfb41cf45af37c2c67e"},{"url":"https://git.kernel.org/stable/c/d129c3177d7b1138fd5066fcc63a698b3ba415b0"}],"title":"net: af_key: initialize alg_key_len for IPComp states","x_generator":{"engine":"bippy-1.2.0"}}}}