{"identifier":"CVE-2026-98116","cve":{"id":"CVE-2026-98116","description":"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.","published":"2026-09-25T11:17:42.780000+00:00","modified":"2026-10-28T16:10:22.600000+00:00","status":"Analyzed","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_version":"3.1","affected":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14.279","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"4.15"},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19.243","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"4.20"},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.193","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"5.5"},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.109","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"5.11"},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.32","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"5.15.222"},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16.18","versionStartExcluding":"","versionEndIncluding":"5.17.1","versionEndExcluding":""},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"6.12.111"},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"6.18.53"},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":"7.2.7"},{"criteria":"cpe:2.3:o:linux:linux_kernel:7.3:rc1:*:*:*:*:*:*","versionStartIncluding":"","versionStartExcluding":"","versionEndIncluding":"","versionEndExcluding":""}],"weaknesses":["CWE-416"],"references":[{"url":"https://git.kernel.org/stable/c/8c1882dfee8f404d118020664b73eb4592172226","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/9857a75714bb5df4781e4d8b1a1753b1e17bf07a","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/9b110a9dcecc59516c77cb3c0caf1f492f75df2d","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/cbadf2575d25e7dcc0d4da2717817ae569fbc99b","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/e6cdd2a0470d64073349a970dc1691433804b271","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/fd137bf8149bc6460f9b7b1fc292025da04cb9ee","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]}],"kev":null,"kev_checked":true,"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14.279","versionEndExcluding":"4.15","matchCriteriaId":"74A30740-4A22-4010-9DE2-ECC961DA4E1F"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19.243","versionEndExcluding":"4.20","matchCriteriaId":"377B69E2-76BA-4327-8D8D-9E978D218DFC"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.193","versionEndExcluding":"5.5","matchCriteriaId":"AFD473DD-DFA3-44BB-B228-3D4572832AF3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.109","versionEndExcluding":"5.11","matchCriteriaId":"B08717F2-D179-40D5-9380-75A360456651"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.32","versionEndExcluding":"5.15.222","matchCriteriaId":"AF7A01DF-61B5-4270-AD0E-63B8C4DD81F0"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16.18","versionEndIncluding":"5.17.1","matchCriteriaId":"13C4237C-3C38-4C41-BFB6-8BD2D9EF33BF"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.111","matchCriteriaId":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