{"id":"CVE-2026-98912","kind":"vulnerability","aliases":["CVE-2026-98912"],"related":[],"title":"Linux kernel ALSA sequencer OSS read check copies events incorrectly","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: oss: Reject reads that cannot fit the next event\n\nsnd_seq_oss_read() checks whether the next queued OSS sequencer event\nfits in the remaining userspace buffer before removing it from the read\nqueue.\n\nThe check is inverted. It currently stops when the event is smaller than\nthe remaining buffer, so a normal 4-byte event is not copied for an\n8-byte read buffer. Conversely, an 8-byte event can be copied for a\nsmaller read count.\n\nBreak only when the remaining userspace buffer is smaller than the next\nevent, and report -EINVAL if no complete event has been copied. This\nprevents an undersized read from looking like end-of-file while leaving\nthe event queued for a later read with a large enough buffer.","summary":"In the Linux kernel's ALSA OSS sequencer, the read path checks whether the next queued event fits the userspace buffer with an inverted comparison. Small reads can copy oversized events and normal events can be skipped, so reads can misbehave or return the wrong result.","severity":"unknown","cvss":null,"epss":0.00215,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["alsa","infrastructure","kernel","linux"],"not_affected_if":["no-oss-sequencer-use"],"how_to_check":"- unknown","fix":"- unknown","status":"open","published_at":"2026-10-23T12:18:25+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","triaged_at":"2026-10-25T04:58:28+00:00","updated_at":"2026-10-25T12:38:50+00:00","category":"infrastructure","confidence":0.4,"triage":{"at":"2026-10-25T04:58:28Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"local","title":"Linux kernel ALSA sequencer OSS read check copies events incorrectly","impact":"low","summary":"In the Linux kernel's ALSA OSS sequencer, the read path checks whether the next queued event fits the userspace buffer with an inverted comparison. Small reads can copy oversized events and normal events can be skipped, so reads can misbehave or return the wrong result.","category":"infrastructure","nicknames":[],"who_cares":["linux","kernel","alsa"],"confidence":0.4,"needs_auth":"unknown","worst_case":"unknown; memory-safety impact not stated in sources","analyst_note":"Check the kernel.org stable commits or the NVD entry for affected version ranges and whether the bad copy leads to memory disclosure or corruption.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["no-oss-sequencer-use"],"who_is_affected":"Systems running a Linux kernel with the ALSA sequencer OSS emulation code (sound/core/seq/oss) that reads from /dev/sequencer. Hosts without the OSS sequencer in use are unlikely to be reached. The sources do not give affected kernel version ranges, so unknown beyond that.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000587,"input_tokens":3484,"output_tokens":477,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':12A,15A '-98912':13A,16A '4':132C '8':140C,146C 'alsa':3A,17B,26B,77C 'break':157C 'buffer':41B,105C,128C,143C,163C,205C 'byte':133C,141C,147C 'cannot':83C 'check':7A,32B,92C,114C 'comparison':45B 'complet':175C 'convers':144C 'copi':8A,49B,137C,151C,179C 'count':156C 'current':118C 'cve':11A,14A 'einval':172C 'end':189C 'end-of-fil':188C 'enough':204C 'event':9A,37B,51B,54B,87C,99C,122C,134C,148C,169C,176C,195C 'file':191C 'fit':38B,84C,100C 'follow':72C 'incorrect':10A 'infrastructur':18B 'invert':44B,116C 'kernel':2A,19B,24B,70C 'larg':203C 'later':199C 'leav':193C 'like':187C 'linux':1A,20B,23B,69C 'look':186C 'misbehav':61B 'next':35B,86C,95C,168C 'normal':53B,131C 'oss':5A,27B,79C,90C,97C 'overs':50B 'path':31B 'prevent':181C 'queu':36B,96C,196C 'queue':112C 'read':6A,30B,47B,59B,81C,91C,111C,142C,155C,184C,200C 'reject':80C 'remain':103C,127C,161C 'remov':107C 'report':171C 'resolv':76C 'result':66B 'return':63B 'seq':78C,89C 'sequenc':4A,28B,98C 'skip':57B 'small':46B 'smaller':124C,154C,165C 'snd':88C 'stop':119C 'unders':183C 'userspac':40B,104C,162C 'vulner':73C 'whether':33B,93C 'wrong':65B","nicknames":[],"mitigations":[],"who_affected":"Systems running a Linux kernel with the ALSA sequencer OSS emulation code (sound/core/seq/oss) that reads from /dev/sequencer. Hosts without the OSS sequencer in use are unlikely to be reached. The sources do not give affected kernel version ranges, so unknown beyond that.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T12:18:25+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98912","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98912","severity":null,"published_at":"2026-10-23T12:18:25+00:00","modified_at":"2026-10-23T12:18:25+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","fetched_at":"2026-10-23T22:29:03+00:00","note":null},{"source":"epss","external_id":"CVE-2026-98912","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98912","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-25T12:38:50+00:00","fetched_at":"2026-10-25T12:38:50+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}