{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64124", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.036Z", "datePublished": "2026-07-19T15:40:21.879Z", "dateUpdated": "2026-08-05T12:39:30.822Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:39:30.822Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/devmem.c" ], "versions": [ { "version": "bd61848900bff597764238f3a8ec67c815cd316e", "lessThan": "134c517dfa63203287b2aad6558017f42435a02e", "status": "affected", "versionType": "git" }, { "version": "bd61848900bff597764238f3a8ec67c815cd316e", "lessThan": "d5008e4e4ee6b739256b796702a7d1aae1b5c3b4", "status": "affected", "versionType": "git" }, { "version": "bd61848900bff597764238f3a8ec67c815cd316e", "lessThan": "4eb82ba543421e9e38cc14e4e82058b78850df50", "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/core/devmem.c" ], "versions": [ { "version": "6.16", "status": "affected" }, { "version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.11", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "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" } ] } ] } ], "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" } ], "title": "net: devmem: reject dma-buf bind with non-page-aligned size or SG length", "x_generator": { "engine": "bippy-1.2.0" } } } }