{"id":"CVE-2026-98116","revision":"acd716cb07864ae1817d1f1835b3bf22","records":[{"revision":"acd716cb07864ae1817d1f1835b3bf22","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98116","aliases":[],"title":"ALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF","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.","state":0,"publishedAt":"2026-09-25T10:36:01.723+00:00","modifiedAt":"2026-10-19T09:14:08.504+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"sound/core/pcm_native.c\"\n ],\n \"versions\": [\n {\n \"version\": \"33061d0fba51d2bf70a2ef9645f703c33fe8e438\",\n \"lessThan\": \"e6cdd2a0470d64073349a970dc1691433804b271\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"92ee3c60ec9fe64404dc035e7c41277d74aa26cb\",\n \"lessThan\": \"9857a75714bb5df4781e4d8b1a1753b1e17bf07a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"92ee3c60ec9fe64404dc035e7c41277d74aa26cb\",\n \"lessThan\": \"cbadf2575d25e7dcc0d4da2717817ae569fbc99b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"92ee3c60ec9fe64404dc035e7c41277d74aa26cb\",\n \"lessThan\": \"cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"92ee3c60ec9fe64404dc035e7c41277d74aa26cb\",\n \"lessThan\": \"fd137bf8149bc6460f9b7b1fc292025da04cb9ee\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"92ee3c60ec9fe64404dc035e7c41277d74aa26cb\",\n \"lessThan\": \"8c1882dfee8f404d118020664b73eb4592172226\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"92ee3c60ec9fe64404dc035e7c41277d74aa26cb\",\n \"lessThan\": \"9b110a9dcecc59516c77cb3c0caf1f492f75df2d\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"a42aa926843acca96c0dfbde2e835b8137f2f092\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9cb6c40a6ebe4a0cfc9d6a181958211682cffea9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"fbeb492694ce0441053de57699e1e2b7bc148a69\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0f6947f5f5208f6ebd4d76a82a4757e2839a23f8\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0090c13cbbdffd7da079ac56f80373a9a1be0bf8\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"1bbf82d9f961414d6c76a08f7f843ea068e0ab7b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"5.15.32\",\n \"lessThan\": \"5.15.222\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.14.279\",\n \"lessThan\": \"4.15\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.19.243\",\n \"lessThan\": \"4.20\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.4.193\",\n \"lessThan\": \"5.5\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.109\",\n \"lessThan\": \"5.11\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.16.18\",\n \"lessThan\": \"5.17\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.17.1\",\n \"lessThan\": \"5.18\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"sound/core/pcm_native.c\"\n ],\n \"versions\": [\n {\n \"version\": \"5.18\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"5.18\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.222\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.189\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.158\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.111\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.53\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.7\",\n \"lessThanOrEqual\": \"7.2.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.3\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/e6cdd2a0470d64073349a970dc1691433804b271","https://git.kernel.org/stable/c/9857a75714bb5df4781e4d8b1a1753b1e17bf07a","https://git.kernel.org/stable/c/cbadf2575d25e7dcc0d4da2717817ae569fbc99b","https://git.kernel.org/stable/c/cbc7ec97601d09b74e05e44470fa6b0bcdabf3f5","https://git.kernel.org/stable/c/fd137bf8149bc6460f9b7b1fc292025da04cb9ee","https://git.kernel.org/stable/c/8c1882dfee8f404d118020664b73eb4592172226","https://git.kernel.org/stable/c/9b110a9dcecc59516c77cb3c0caf1f492f75df2d"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98116","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98116","identifiers":["CVE-2026-98116"]},"retained":false,"historicalAffected":[]}],"coverage":[]}