{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64449", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.788Z", "datePublished": "2026-07-25T08:51:19.537Z", "dateUpdated": "2026-08-17T04:55:52.942Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:55:52.942Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nstaging: vme_user: bound slave read/write to the kern_buf size\n\nThe SLAVE-path helpers buffer_to_user() and buffer_from_user() copy\n'count' bytes into/out of the fixed-size kern_buf (size_buf ==\nPCI_BUF_SIZE == 0x20000, 128 KiB) using *ppos as the offset, without\nbounding *ppos + count against size_buf.\n\nvme_user_write()/vme_user_read() only clamp count to the VME window size\n(image_size = vme_get_size(resource)), which VME_SET_SLAVE sets from the\nuser-supplied slave.size -- validated against the VME address space (up\nto VME_A32_MAX = 4 GiB), not against PCI_BUF_SIZE. When the window\nexceeds 128 KiB, a write()/read() copies past the kern_buf allocation.\n\nClamp count against size_buf in both helpers, with an early return when\n*ppos is already at/after the buffer end. *ppos is >= 0 here (the caller\nrejects negative offsets), so size_buf - *ppos cannot wrap. This mirrors\nthe existing clamp in the MASTER-path helpers resource_to_user() /\nresource_from_user(), and matches the read()/write() convention of a\nshort transfer at end-of-buffer.\n\nFound by static analysis (CodeQL taint tracking + CBMC bounded model\nchecking) and confirmed dynamically under KASAN with the vme_fake bridge:\n\n BUG: KASAN: slab-out-of-bounds in _copy_from_user+0x2d/0x80\n Write of size 262144 at addr ffff888004100000 by task trigger/68\n _copy_from_user+0x2d/0x80\n vme_user_write+0x13e/0x240 [vme_user]\n vfs_write+0x1b8/0x7a0\n ksys_write+0xb8/0x150" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable path is reached through ioctl(), lseek(), read(), and write() on a local /dev/bus/vme/s* character device. Network or physical VME-bus input is not needed.\nAC:L - The attacker can deterministically configure an aligned slave window larger than 128 KiB and select the copy offset and length; no race or external condition is required. A 256 KiB overflow was dynamically confirmed under KASAN.\nPR:L - The driver performs no capability or namespace-specific check, so an ordinary account granted access to the VME device node can configure and trigger the flaw. Although devtmpfs defaults to root-owned mode 0600, non-root access for an industrial control or service account is a reasonable deployment.\nUI:N - The attacker independently performs the configuration and malicious read or write without requiring any victim action.\nS:U - Exploitation compromises the host kernel within the same security authority. This is a standard local privilege-escalation condition, not a VM, sandbox, or IOMMU boundary escape.\nC:H - The read path copies an attacker-selected, potentially very large range of kernel memory beyond the 128 KiB allocation to userspace. This can disclose adjacent allocations, kernel pointers, credentials, and other sensitive memory.\nI:H - The write path copies attacker-controlled bytes beyond the DMA or large-kmalloc allocation, potentially across many adjacent physical pages. This provides exploitable memory corruption capable of modifying kernel objects or achieving control-flow hijacking.\nA:H - The out-of-bounds write was confirmed to trigger a KASAN kernel memory-safety failure and can corrupt or access invalid adjacent memory. A kernel oops or panic can be triggered without user interaction." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/staging/vme_user/vme_user.c" ], "versions": [ { "version": "f00a86d98a1ec3e99d352cda926fab767ba43b1f", "lessThan": "65358d89dc9f1c25d9364b2b3ef0f3b47717f9ed", "status": "affected", "versionType": "git" }, { "version": "f00a86d98a1ec3e99d352cda926fab767ba43b1f", "lessThan": "adc8b9c30d716c362646edb45662aa1c641a154a", "status": "affected", "versionType": "git" }, { "version": "f00a86d98a1ec3e99d352cda926fab767ba43b1f", "lessThan": "8eff7cd4817e14dbe3b9952cce55ef52d1d38940", "status": "affected", "versionType": "git" }, { "version": "f00a86d98a1ec3e99d352cda926fab767ba43b1f", "lessThan": "e99f2df433c63c86c93de1e5f08f16e404388756", "status": "affected", "versionType": "git" }, { "version": "f00a86d98a1ec3e99d352cda926fab767ba43b1f", "lessThan": "1b495fa0d4927c88d88bf346bf311f2e26e860ed", "status": "affected", "versionType": "git" }, { "version": "f00a86d98a1ec3e99d352cda926fab767ba43b1f", "lessThan": "9f32f38265014fac7f5dc9490fb01a638ce6e121", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/staging/vme_user/vme_user.c" ], "versions": [ { "version": "2.6.32", "status": "affected" }, { "version": "0", "lessThan": "2.6.32", "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": "2.6.32", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "6.18.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/65358d89dc9f1c25d9364b2b3ef0f3b47717f9ed" }, { "url": "https://git.kernel.org/stable/c/adc8b9c30d716c362646edb45662aa1c641a154a" }, { "url": "https://git.kernel.org/stable/c/8eff7cd4817e14dbe3b9952cce55ef52d1d38940" }, { "url": "https://git.kernel.org/stable/c/e99f2df433c63c86c93de1e5f08f16e404388756" }, { "url": "https://git.kernel.org/stable/c/1b495fa0d4927c88d88bf346bf311f2e26e860ed" }, { "url": "https://git.kernel.org/stable/c/9f32f38265014fac7f5dc9490fb01a638ce6e121" } ], "title": "staging: vme_user: bound slave read/write to the kern_buf size", "x_generator": { "engine": "bippy-1.2.0" } } } }