{"cve":"CVE-2026-74641","nvd":{"published":"2026-08-22T16:16:37.383","modified":"2026-10-16T20:17:49.133","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usx2y: bound the hwdep mmap fault offset\n\nsnd_us428ctls_vm_fault() turns the faulting page offset into a kernel\naddress with no bound of any kind:\n\n\toffset = vmf->pgoff << PAGE_SHIFT;\n\tvaddr = (char *)(...)->us428ctls_sharedmem + offset;\n\tpage = virt_to_page(vaddr);\n\tget_page(page);\n\tvmf->page = page;\n\n\treturn 0;\n\nsnd_us428ctls_mmap() checks only the length of the mapping, never the\noffset, and us428ctls_sharedmem is a single page from\nalloc_pages_exact().  For a character device file_mmap_size_max()\nreturns ULONG_MAX, so the mm layer imposes no ceiling either.  Every page\noffset above zero resolves to a struct page outside the object, and the\nhandler installs it into the caller's address space read-write; the vma\nis not marked read-only.\n\nThe caller picks the page frame with a single mmap() argument and gets\nread-write access to a page of kernel memory it does not own; an offset\nthat lands in an unpopulated vmemmap region oopses instead.\n\nA process that can open the hwdep node of an attached US-X2Y reaches\nthis after loading the FPGA image through the same node; no capability\ncheck is involved.\n\nOn 7.2.0-rc5 (arm64), mmap() with a large offset:\n\n  Unable to handle kernel paging request at virtual address fffffdffc45d5ac8\n  pc : snd_us428ctls_vm_fault+0x68/0x140 [snd_usb_usx2y]\n  Call trace:\n   snd_us428ctls_vm_fault+0x68/0x140 [snd_usb_usx2y]\n   __do_fault\n   __handle_mm_fault\n   handle_mm_fault\n   el0_da\n\nReject any offset outside the shared region.  The pcm hwdep handler in\nusx2yhwdeppcm.c computes its address the same way and needs the same\nbound.\n\nDiscovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/10a87401fb3148c388e55df0148295b3b137da07","https://git.kernel.org/stable/c/2ca1eea3cd17930daffe9e429a7c89232036ec24","https://git.kernel.org/stable/c/34ab56ed854baa73a731cfd99af689f0b1bac444","https://git.kernel.org/stable/c/4208db2453e1ea71b8048a5b7802360cb29a53f1","https://git.kernel.org/stable/c/5bf5ccddf00b59f1e3ea7e65d76a5f5b5c21cc2e"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:38.260478770+00:00"},"epss":{"cve":"CVE-2026-74641","score":0.00129,"percentile":0.02541,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}