CVE-2026-74641 (CVSS 7.8)

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 <[email protected]>

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0013

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other 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 https://git.kernel.org/stable/c/ad6fedea65c6e90eda00d716c8bf20cdc437ed10 https://git.kernel.org/stable/c/f613b4a2d87247b51a1b2b330f2e083a454125f2 https://git.kernel.org/stable/c/f75d6f61f0d9c5c1ea725104014e10d26d1e3a00

Frequently Asked Questions

What is CVE-2026-74641? +

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 <[email protected]> It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-74641? +

CVE-2026-74641 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0013, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-74641? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-74641