ALSA: usx2y: bound the hwdep mmap fault offset

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74641
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-22 16:16:37 UTC
Updated2026-08-22 16:16:37 UTC
DescriptionIn 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 <[email protected]>

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 10a87401fb3148c388e55df0148295b3b137da07 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 34ab56ed854baa73a731cfd99af689f0b1bac444 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 4208db2453e1ea71b8048a5b7802360cb29a53f1 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 f613b4a2d87247b51a1b2b330f2e083a454125f2 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 f75d6f61f0d9c5c1ea725104014e10d26d1e3a00 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 5bf5ccddf00b59f1e3ea7e65d76a5f5b5c21cc2e git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 2ca1eea3cd17930daffe9e429a7c89232036ec24 git Not specified
CNA Linux Linux affected 2.6.12 Not specified
CNA Linux Linux unaffected 2.6.12 semver Not specified
CNA Linux Linux unaffected 5.15.216 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.152 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.104 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.45 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.9 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/2ca1eea3cd17930daffe9e429a7c89232036ec24 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/10a87401fb3148c388e55df0148295b3b137da07 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f613b4a2d87247b51a1b2b330f2e083a454125f2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/5bf5ccddf00b59f1e3ea7e65d76a5f5b5c21cc2e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f75d6f61f0d9c5c1ea725104014e10d26d1e3a00 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4208db2453e1ea71b8048a5b7802360cb29a53f1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/34ab56ed854baa73a731cfd99af689f0b1bac444 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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