{"id":"CVE-2026-98116","title":"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 per…","summary":"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 per…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= 33061d0fba51d2bf70a2ef9645f703c33fe8e438 < e6cdd2a0470d64073349a970dc1691433804b271","Linux >= 92ee3c60ec9fe64404dc035e7c41277d74aa26cb < 9857a75714bb5df4781e4d8b1a1753b1e17bf07a","Linux >= 92ee3c60ec9fe64404dc035e7c41277d74aa26cb < cbadf2575d25e7dcc0d4da2717817ae569fbc99b","Linux >= 92ee3c60ec9fe64404dc035e7c41277d74aa26cb < cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5","Linux >= 92ee3c60ec9fe64404dc035e7c41277d74aa26cb < fd137bf8149bc6460f9b7b1fc292025da04cb9ee","Linux >= 92ee3c60ec9fe64404dc035e7c41277d74aa26cb < 8c1882dfee8f404d118020664b73eb4592172226","Linux >= 92ee3c60ec9fe64404dc035e7c41277d74aa26cb < 9b110a9dcecc59516c77cb3c0caf1f492f75df2d","Linux a42aa926843acca96c0dfbde2e835b8137f2f092","Linux 9cb6c40a6ebe4a0cfc9d6a181958211682cffea9","Linux fbeb492694ce0441053de57699e1e2b7bc148a69","Linux 0f6947f5f5208f6ebd4d76a82a4757e2839a23f8","Linux 0090c13cbbdffd7da079ac56f80373a9a1be0bf8","Linux 1bbf82d9f961414d6c76a08f7f843ea068e0ab7b","Linux >= 5.15.32 < 5.15.222","Linux >= 4.14.279 < 4.15","Linux >= 4.19.243 < 4.20","Linux >= 5.4.193 < 5.5","Linux >= 5.10.109 < 5.11","Linux >= 5.16.18 < 5.17","Linux >= 5.17.1 < 5.18","Linux 5.18"],"published":"2026-09-25","updated":"2026-10-03","sourceUpdated":"2026-10-03T11:18:33.517","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98116","references":[{"url":"https://git.kernel.org/stable/c/8c1882dfee8f404d118020664b73eb4592172226","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9857a75714bb5df4781e4d8b1a1753b1e17bf07a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9b110a9dcecc59516c77cb3c0caf1f492f75df2d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cbadf2575d25e7dcc0d4da2717817ae569fbc99b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e6cdd2a0470d64073349a970dc1691433804b271","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fd137bf8149bc6460f9b7b1fc292025da04cb9ee","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98116.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-98116"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541360"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98116"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98116"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98116.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00126,"epssPercentile":0.0228,"scores":{"nvd":7.8,"vendor":7,"cna":7.8},"ingestedAt":"2026-09-25T11:06:38.822Z","slug":"CVE-2026-98116","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-09-30 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98116.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":210898,"id":"CVE-2026-98116","ts":1790349113895,"field":"cvss","old":null,"new":"7.8"},{"seq":210897,"id":"CVE-2026-98116","ts":1790349113895,"field":"severity","old":"none","new":"high"}]}