{"id":"CVE-2026-64124","state":"PUBLISHED","title":"net: devmem: reject dma-buf bind with non-page-aligned size or SG length","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: devmem: reject dma-buf bind with non-page-aligned size or SG length\n\nnet_devmem_bind_dmabuf() trusts dmabuf->size and sg_dma_len() to be\nPAGE_SIZE multiples without checking:\n\n  - tx_vec is sized dmabuf->size / PAGE_SIZE, and\n    net_devmem_get_niov_at() only bounds-checks virt_addr < dmabuf->size\n    before indexing tx_vec[virt_addr / PAGE_SIZE]. With size =\n    N*PAGE_SIZE + r (1 <= r < PAGE_SIZE), sendmsg() at iov_base =\n    N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past.\n\n  - owner->area.num_niovs = len / PAGE_SIZE while gen_pool_add_owner()\n    covers the full byte len, so a non-page-multiple non-final sg\n    desyncs num_niovs from the gen_pool region for every later sg, on\n    both RX and TX.\n\ndma-buf does not require page-aligned sizes, so the bind path has to\nenforce what its own indexing assumes. Reject both with -EINVAL.\n\nThe size check is TX-only (only tx_vec is sized off dmabuf->size); the\nSG-length check covers both directions.","publishedAt":"2026-07-19T15:40:21.879Z","updatedAt":"2026-08-05T12:39:30.822Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bd61848900bff597764238f3a8ec67c815cd316e","status":"affected","lessThan":"134c517dfa63203287b2aad6558017f42435a02e","versionType":"git"},{"version":"bd61848900bff597764238f3a8ec67c815cd316e","status":"affected","lessThan":"d5008e4e4ee6b739256b796702a7d1aae1b5c3b4","versionType":"git"},{"version":"bd61848900bff597764238f3a8ec67c815cd316e","status":"affected","lessThan":"4eb82ba543421e9e38cc14e4e82058b78850df50","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/devmem.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.18.35","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/devmem.c"]}],"references":["https://git.kernel.org/stable/c/134c517dfa63203287b2aad6558017f42435a02e","https://git.kernel.org/stable/c/d5008e4e4ee6b739256b796702a7d1aae1b5c3b4","https://git.kernel.org/stable/c/4eb82ba543421e9e38cc14e4e82058b78850df50"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64124.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64124","state":"PUBLISHED","datePublished":"2026-07-19T15:40:21.879Z","dateUpdated":"2026-08-05T12:39:30.822Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.036Z"},"containers":{"cna":{"title":"net: devmem: reject dma-buf bind with non-page-aligned size or SG length","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: devmem: reject dma-buf bind with non-page-aligned size or SG length\n\nnet_devmem_bind_dmabuf() trusts dmabuf->size and sg_dma_len() to be\nPAGE_SIZE multiples without checking:\n\n  - tx_vec is sized dmabuf->size / PAGE_SIZE, and\n    net_devmem_get_niov_at() only bounds-checks virt_addr < dmabuf->size\n    before indexing tx_vec[virt_addr / PAGE_SIZE]. With size =\n    N*PAGE_SIZE + r (1 <= r < PAGE_SIZE), sendmsg() at iov_base =\n    N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past.\n\n  - owner->area.num_niovs = len / PAGE_SIZE while gen_pool_add_owner()\n    covers the full byte len, so a non-page-multiple non-final sg\n    desyncs num_niovs from the gen_pool region for every later sg, on\n    both RX and TX.\n\ndma-buf does not require page-aligned sizes, so the bind path has to\nenforce what its own indexing assumes. Reject both with -EINVAL.\n\nThe size check is TX-only (only tx_vec is sized off dmabuf->size); the\nSG-length check covers both directions."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bd61848900bff597764238f3a8ec67c815cd316e","status":"affected","lessThan":"134c517dfa63203287b2aad6558017f42435a02e","versionType":"git"},{"version":"bd61848900bff597764238f3a8ec67c815cd316e","status":"affected","lessThan":"d5008e4e4ee6b739256b796702a7d1aae1b5c3b4","versionType":"git"},{"version":"bd61848900bff597764238f3a8ec67c815cd316e","status":"affected","lessThan":"4eb82ba543421e9e38cc14e4e82058b78850df50","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/devmem.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.18.35","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/devmem.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/134c517dfa63203287b2aad6558017f42435a02e"},{"url":"https://git.kernel.org/stable/c/d5008e4e4ee6b739256b796702a7d1aae1b5c3b4"},{"url":"https://git.kernel.org/stable/c/4eb82ba543421e9e38cc14e4e82058b78850df50"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires local syscalls—NETLINK_GENERIC netdev bind operations and sendmsg/recvmsg on TCP sockets—not remote packet delivery. Network traffic can trigger RX allocations only after a local bind with a malformed dmabuf.\nAC:L - The attacker fully controls dmabuf size/SG layout at bind time and the virtual offset passed via sendmsg iovec bases, allowing reliable out-of-bounds indexing without races or victim-dependent timing.\nPR:L - TX bind intentionally lacks admin-perm; RX bind requires CAP_NET_ADMIN, which is obtainable in user namespaces via unshare. No real-root privileges are needed, only a local authorized user on a devmem-capable system.\nUI:N - No victim interaction is required; the attacker triggers the bug through their own netlink bind and socket operations.\nS:C - Corrupted net_iov metadata can program incorrect DMA addresses for NIC DMA operations, potentially impacting device memory outside the kernel's security authority—a DMA boundary crossing inherent to the devmem subsystem.\nC:H - Out-of-bounds read of tx_vec leaks adjacent kernel heap contents (kernel pointers), and heap corruption from misindexed niovs arrays can be leveraged for arbitrary memory disclosure.\nI:H - Out-of-bounds writes to the niovs array corrupt adjacent kernel heap objects, and use of attacker-influenced pointers in skb fragment setup enables memory corruption exploitable for control-flow hijacking.\nA:H - Dereferencing corrupted net_iov pointers or corrupting heap metadata via out-of-bounds access can cause kernel oops, panic, or hang during TX sendmsg or RX packet processing."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:39:30.822Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.18.35"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}