{"id":"CVE-2026-31778","title":"ALSA: caiaq: fix stack out-of-bounds read in init_card","summary":"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 < sizeof(card->id)` is used for the…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 02d9c5b0b5553a391448b6d655262bd829f90234","Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6","Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 66194c2575a4f567577ae70b1d7561163ce791a6","Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < a82c1bce2d1299dd3c686a8fe48cf75b79a403c7","Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 3178b62e2e31bab39f63d4c8e54bf4ee0a425627","Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 3afa2e67f3523a980a2f90fd63c22322ac2b9ce0","Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 7594a6464873d90fd229e5b94cdd3b92c9feabed","Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 45424e871abf2a152e247a9cff78359f18dd95c0","Linux 2.6.31"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T15:25:25.500479Z"},"published":"2026-05-01","updated":"2026-11-06","sourceUpdated":"2026-11-06T15:32:25.311Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31778","references":[{"url":"https://git.kernel.org/stable/c/02d9c5b0b5553a391448b6d655262bd829f90234"},{"url":"https://git.kernel.org/stable/c/3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6"},{"url":"https://git.kernel.org/stable/c/66194c2575a4f567577ae70b1d7561163ce791a6"},{"url":"https://git.kernel.org/stable/c/a82c1bce2d1299dd3c686a8fe48cf75b79a403c7"},{"url":"https://git.kernel.org/stable/c/3178b62e2e31bab39f63d4c8e54bf4ee0a425627"},{"url":"https://git.kernel.org/stable/c/3afa2e67f3523a980a2f90fd63c22322ac2b9ce0"},{"url":"https://git.kernel.org/stable/c/7594a6464873d90fd229e5b94cdd3b92c9feabed"},{"url":"https://git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0"}],"tags":["cve.org"],"epss":0.00126,"epssPercentile":0.02284,"ingestedAt":"2026-11-06T15:54:04.040Z","slug":"CVE-2026-31778","body":"## Overview\n\nIn 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 < sizeof(card->id)` is used for the bounds check. Since\nsizeof(card->id) 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() -> 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->id) - 1`,\nensuring at least one byte remains as the null terminator.\n\n## Affected\n\n- `Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 02d9c5b0b5553a391448b6d655262bd829f90234`\n- `Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6`\n- `Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 66194c2575a4f567577ae70b1d7561163ce791a6`\n- `Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < a82c1bce2d1299dd3c686a8fe48cf75b79a403c7`\n- `Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 3178b62e2e31bab39f63d4c8e54bf4ee0a425627`\n- `Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 3afa2e67f3523a980a2f90fd63c22322ac2b9ce0`\n- `Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 7594a6464873d90fd229e5b94cdd3b92c9feabed`\n- `Linux >= bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a < 45424e871abf2a152e247a9cff78359f18dd95c0`\n- `Linux 2.6.31`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}