{"id":"CVE-2026-97931","summary":"ALSA: us122l: Prevent write upgrades for read mappings","details":"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.","modified":"2026-10-09T17:27:01.243264228Z","published":"2026-09-25T10:22:47.382Z","related":["openSUSE-SU-2026:12074-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97931.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/64a87950239867682cde128020e1a47088295e5c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6a5f5a5a32c78e67701f1d0f26bc87af68895604"},{"type":"WEB","url":"https://git.kernel.org/stable/c/71c610aeb1770302ac9c9e0b9a4ecd37f1311928"},{"type":"WEB","url":"https://git.kernel.org/stable/c/938e8d6cee8d36f24669dfdcd3717e081eb32d64"},{"type":"WEB","url":"https://git.kernel.org/stable/c/becb89036a1320ef0a77da2d27935ac0704345c4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cbc1f954ce67d739d41d1f0757d29850353ebb6a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d9c537b14f4982f17b103e3a2cfeee4bee6bc026"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97931.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97931"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"030a07e441296c372f946cd4065b5d831d8dc40c"},{"fixed":"cbc1f954ce67d739d41d1f0757d29850353ebb6a"},{"fixed":"becb89036a1320ef0a77da2d27935ac0704345c4"},{"fixed":"6a5f5a5a32c78e67701f1d0f26bc87af68895604"},{"fixed":"938e8d6cee8d36f24669dfdcd3717e081eb32d64"},{"fixed":"64a87950239867682cde128020e1a47088295e5c"},{"fixed":"d9c537b14f4982f17b103e3a2cfeee4bee6bc026"},{"fixed":"0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f"},{"fixed":"71c610aeb1770302ac9c9e0b9a4ecd37f1311928"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-97931.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.28"},{"fixed":"5.10.271"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.222"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.189"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.158"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-97931.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}