{"schema":"threatline.record/2","record":{"id":"CVE-2026-98116","aliases":[],"summary":"ALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF\n\nsnd_pcm_hw_params() and snd_pcm_hw_free() guard buffer reallocation\nwith an mmap_count check performed under the PCM stream lock, but the\nlock is released long before the buffer is actually freed:\nsnd_pcm_sync_stop(), constraint refinement and do_free_pages() all\nhappen in between.  snd_pcm_mmap_data(), on the other hand, takes no\nlock at all: it validates against the old buffer's state and\ndma_bytes, remaps its pages into the VMA, and only then increments\nmmap_count.\n\nA concurrent mmap() can therefore slip in between the check and the\nfree.  remap_pfn_range() installs writable PTEs for the old buffer's\npages without taking page references, and the subsequent\ndo_free_pages() returns those pages to the page allocator while the\nVMA still maps them.  This leaves a stale, writable mapping of freed\npages: a page-level use-after-free that can be leveraged for local\nprivilege escalation.\n\nMake snd_pcm_mmap_data() participate in the buffer-access scheme\nintroduced for hw_params/hw_free: acquire runtime->buffer_accessing\nbefore validating and remapping, and release it afterwards.  Buffer\nreallocation already fails with -EBUSY while accessors are active,\nand the mmap side now fails with -EBUSY while a reallocation is in\nprogress, so the validate/remap sequence and the check/free sequence\ncan no longer interleave.\n\nA reproducer that turns this race into a stale writable mapping of\nthe freed DMA buffer pages is available on request.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98116","source_modified_at":"2026-10-19T09:14:08.504Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"33061d0fba51d2bf70a2ef9645f703c33fe8e438","lessThan":"e6cdd2a0470d64073349a970dc1691433804b271","status":"affected","versionType":"git"},{"version":"92ee3c60ec9fe64404dc035e7c41277d74aa26cb","lessThan":"9857a75714bb5df4781e4d8b1a1753b1e17bf07a","status":"affected","versionType":"git"},{"version":"92ee3c60ec9fe64404dc035e7c41277d74aa26cb","lessThan":"cbadf2575d25e7dcc0d4da2717817ae569fbc99b","status":"affected","versionType":"git"},{"version":"92ee3c60ec9fe64404dc035e7c41277d74aa26cb","lessThan":"cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5","status":"affected","versionType":"git"},{"version":"92ee3c60ec9fe64404dc035e7c41277d74aa26cb","lessThan":"fd137bf8149bc6460f9b7b1fc292025da04cb9ee","status":"affected","versionType":"git"},{"version":"92ee3c60ec9fe64404dc035e7c41277d74aa26cb","lessThan":"8c1882dfee8f404d118020664b73eb4592172226","status":"affected","versionType":"git"},{"version":"92ee3c60ec9fe64404dc035e7c41277d74aa26cb","lessThan":"9b110a9dcecc59516c77cb3c0caf1f492f75df2d","status":"affected","versionType":"git"},{"version":"a42aa926843acca96c0dfbde2e835b8137f2f092","status":"affected","versionType":"git"},{"version":"9cb6c40a6ebe4a0cfc9d6a181958211682cffea9","status":"affected","versionType":"git"},{"version":"fbeb492694ce0441053de57699e1e2b7bc148a69","status":"affected","versionType":"git"},{"version":"0f6947f5f5208f6ebd4d76a82a4757e2839a23f8","status":"affected","versionType":"git"},{"version":"0090c13cbbdffd7da079ac56f80373a9a1be0bf8","status":"affected","versionType":"git"},{"version":"1bbf82d9f961414d6c76a08f7f843ea068e0ab7b","status":"affected","versionType":"git"},{"version":"5.15.32","lessThan":"5.15.222","status":"affected","versionType":"semver"},{"version":"4.14.279","lessThan":"4.15","status":"affected","versionType":"semver"},{"version":"4.19.243","lessThan":"4.20","status":"affected","versionType":"semver"},{"version":"5.4.193","lessThan":"5.5","status":"affected","versionType":"semver"},{"version":"5.10.109","lessThan":"5.11","status":"affected","versionType":"semver"},{"version":"5.16.18","lessThan":"5.17","status":"affected","versionType":"semver"},{"version":"5.17.1","lessThan":"5.18","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98116","source_modified_at":"2026-10-19T09:14:08.504Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.18","status":"affected"},{"version":"0","lessThan":"5.18","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98116","source_modified_at":"2026-10-19T09:14:08.504Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"9857a75714bb5df4781e4d8b1a1753b1e17bf07a","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98116","source_modified_at":"2026-10-19T09:14:08.504Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"8c1882dfee8f404d118020664b73eb4592172226","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98116","source_modified_at":"2026-10-19T09:14:08.504Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"9b110a9dcecc59516c77cb3c0caf1f492f75df2d","basis":"first unaffected version stated in the CVE record"},{"source":"CVE 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List","url":"https://git.kernel.org/stable/c/9857a75714bb5df4781e4d8b1a1753b1e17bf07a"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/cbadf2575d25e7dcc0d4da2717817ae569fbc99b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/fd137bf8149bc6460f9b7b1fc292025da04cb9ee"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/8c1882dfee8f404d118020664b73eb4592172226"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/9b110a9dcecc59516c77cb3c0caf1f492f75df2d"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:14:08.504Z","content_hash":"9c54dab070e3a06295112c7b7375159a86f843fd9879267c98f4d1ff51221c68"}}