{"id":"CVE-2026-97931","published":"2026-09-25T11:17:20.387","lastModified":"2026-09-25T15:18:02.450","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: us122l: Prevent write upgrades for read mappings\n\nThe hwdep mmap callback rejects read-buffer mappings that are initially\nwritable, but leaves VM_MAYWRITE set on mappings created with PROT_READ.\nA process that can open the hwdep node O_RDWR can later use mprotect() to\nmake the mapping writable.\n\nThe read allocation begins with struct usb_stream. Its read_size member is\nused by the fault handler to decide which pages belong to the read buffer.\nThe read VMA intentionally remains expandable because pcm_usb_stream uses\nmremap() after reading that size. Changing read_size first can therefore\nmap and access pages beyond the allocation. The same member is also\nconsumed by usb_stream_free(), where changing it can make\nfree_pages_exact() release pages outside the allocation.\n\nClear VM_MAYWRITE for read-buffer mappings after rejecting an initially\nwritable VMA. This keeps the separate output-buffer mapping writable while\npreventing later permission upgrades.","cvssScore":7,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f","tags":[]},{"url":"https://git.kernel.org/stable/c/64a87950239867682cde128020e1a47088295e5c","tags":[]},{"url":"https://git.kernel.org/stable/c/71c610aeb1770302ac9c9e0b9a4ecd37f1311928","tags":[]},{"url":"https://git.kernel.org/stable/c/d9c537b14f4982f17b103e3a2cfeee4bee6bc026","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}