{"id":"CVE-2026-31778","summary":"ALSA: caiaq: fix stack out-of-bounds read in init_card","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: caiaq: fix stack out-of-bounds read in init_card\n\nThe loop creates a whitespace-stripped copy of the card shortname\nwhere `len \u003c sizeof(card-\u003eid)` is used for the bounds check. Since\nsizeof(card-\u003eid) is 16 and the local id buffer is also 16 bytes,\nwriting 16 non-space characters fills the entire buffer,\noverwriting the terminating nullbyte.\n\nWhen this non-null-terminated string is later passed to\nsnd_card_set_id() -\u003e copy_valid_id_string(), the function scans\nforward with `while (*nid && ...)` and reads past the end of the\nstack buffer, reading the contents of the stack.\n\nA USB device with a product name containing many non-ASCII, non-space\ncharacters (e.g. multibyte UTF-8) will reliably trigger this as follows:\n\n  BUG: KASAN: stack-out-of-bounds in copy_valid_id_string\n       sound/core/init.c:696 [inline]\n  BUG: KASAN: stack-out-of-bounds in snd_card_set_id_no_lock+0x698/0x74c\n       sound/core/init.c:718\n\nThe off-by-one has been present since commit bafeee5b1f8d (\"ALSA:\nsnd_usb_caiaq: give better shortname\") from June 2009 (v2.6.31-rc1),\nwhich first introduced this whitespace-stripping loop. The original\ncode never accounted for the null terminator when bounding the copy.\n\nFix this by changing the loop bound to `sizeof(card-\u003eid) - 1`,\nensuring at least one byte remains as the null terminator.","modified":"2026-06-19T08:29:26.742045506Z","published":"2026-05-01T14:15:05.804Z","related":["SUSE-SU-2026:2450-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31778.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/02d9c5b0b5553a391448b6d655262bd829f90234"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3178b62e2e31bab39f63d4c8e54bf4ee0a425627"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3afa2e67f3523a980a2f90fd63c22322ac2b9ce0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/66194c2575a4f567577ae70b1d7561163ce791a6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7594a6464873d90fd229e5b94cdd3b92c9feabed"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a82c1bce2d1299dd3c686a8fe48cf75b79a403c7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31778.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31778"},{"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":"bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a"},{"fixed":"02d9c5b0b5553a391448b6d655262bd829f90234"},{"fixed":"3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6"},{"fixed":"66194c2575a4f567577ae70b1d7561163ce791a6"},{"fixed":"a82c1bce2d1299dd3c686a8fe48cf75b79a403c7"},{"fixed":"3178b62e2e31bab39f63d4c8e54bf4ee0a425627"},{"fixed":"3afa2e67f3523a980a2f90fd63c22322ac2b9ce0"},{"fixed":"7594a6464873d90fd229e5b94cdd3b92c9feabed"},{"fixed":"45424e871abf2a152e247a9cff78359f18dd95c0"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31778.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.31"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.168"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.134"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.22"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31778.json"}}],"schema_version":"1.7.5"}