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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-74641

ALSA: usx2y: bound the hwdep mmap fault offset

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usx2y: bound the hwdep mmap fault offset snd_us428ctls_vm_fault() turns the faulting page offset into a kernel address with no bound of any kind: offset = vmf->pgoff << PAGE_SHIFT; vaddr = (char *)(...)->us428ctls_sharedmem + offset; page = virt_to_page(vaddr); get_page(page); vmf->page = page; return 0; snd_us428ctls_mmap() checks only the length of the mapping, never the offset, and us428ctls_sharedmem is a single page from alloc_pages_exact(). For a character device file_mmap_size_max() returns ULONG_MAX, so the mm layer imposes no ceiling either. Every page offset above zero resolves to a struct page outside the object, and the handler installs it into the caller's address space read-write; the vma is not marked read-only. The caller picks the page frame with a single mmap() argument and gets read-write access to a page of kernel memory it does not own; an offset that lands in an unpopulated vmemmap region oopses instead. A process that can open the hwdep node of an attached US-X2Y reaches this after loading the FPGA image through the same node; no capability check is involved. On 7.2.0-rc5 (arm64), mmap() with a large offset: Unable to handle kernel paging request at virtual address fffffdffc45d5ac8 pc : snd_us428ctls_vm_fault+0x68/0x140 [snd_usb_usx2y] Call trace: snd_us428ctls_vm_fault+0x68/0x140 [snd_usb_usx2y] __do_fault __handle_mm_fault handle_mm_fault el0_da Reject any offset outside the shared region. The pcm hwdep handler in usx2yhwdeppcm.c computes its address the same way and needs the same bound. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < ad6fedea65c6e90eda00d716c8bf20cdc437ed10affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 10a87401fb3148c388e55df0148295b3b137da07affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 34ab56ed854baa73a731cfd99af689f0b1bac444affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 4208db2453e1ea71b8048a5b7802360cb29a53f1affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < f613b4a2d87247b51a1b2b330f2e083a454125f2affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < f75d6f61f0d9c5c1ea725104014e10d26d1e3a00affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 5bf5ccddf00b59f1e3ea7e65d76a5f5b5c21cc2eaffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 2ca1eea3cd17930daffe9e429a7c89232036ec24affected

Linux Linux

Default version status: affected

  • 2.6.12affected
  • 0 to < 2.6.12unaffected
  • 5.10.266 to ≤ 5.10.*unaffected
  • 5.15.216 to ≤ 5.15.*unaffected
  • 6.1.183 to ≤ 6.1.*unaffected
  • 6.6.152 to ≤ 6.6.*unaffected
  • 6.12.104 to ≤ 6.12.*unaffected
  • 6.18.45 to ≤ 6.18.*unaffected
  • 7.1.9 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References