{ "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 \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 \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" } } } }