{"api_version":"1","generated_at":"2026-10-26T07:11:16+00:00","cve":"CVE-2026-97931","urls":{"html":"https://cve.report/CVE-2026-97931","api":"https://cve.report/api/cve/CVE-2026-97931.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-97931","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-97931"},"summary":{"title":"ALSA: us122l: Prevent write upgrades for read mappings","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: us122l: Prevent write upgrades for read mappings\n\nThe hwdep mmap callback rejects read-buffer mappings that are initially\nwritable, but leaves VM_MAYWRITE set on mappings created with PROT_READ.\nA process that can open the hwdep node O_RDWR can later use mprotect() to\nmake the mapping writable.\n\nThe read allocation begins with struct usb_stream. Its read_size member is\nused by the fault handler to decide which pages belong to the read buffer.\nThe read VMA intentionally remains expandable because pcm_usb_stream uses\nmremap() after reading that size. Changing read_size first can therefore\nmap and access pages beyond the allocation. The same member is also\nconsumed by usb_stream_free(), where changing it can make\nfree_pages_exact() release pages outside the allocation.\n\nClear VM_MAYWRITE for read-buffer mappings after rejecting an initially\nwritable VMA. This keeps the separate output-buffer mapping writable while\npreventing later permission upgrades.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-25 11:17:20","updated_at":"2026-10-19 10:17:43"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/64a87950239867682cde128020e1a47088295e5c","name":"https://git.kernel.org/stable/c/64a87950239867682cde128020e1a47088295e5c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cbc1f954ce67d739d41d1f0757d29850353ebb6a","name":"https://git.kernel.org/stable/c/cbc1f954ce67d739d41d1f0757d29850353ebb6a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f","name":"https://git.kernel.org/stable/c/0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/938e8d6cee8d36f24669dfdcd3717e081eb32d64","name":"https://git.kernel.org/stable/c/938e8d6cee8d36f24669dfdcd3717e081eb32d64","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d9c537b14f4982f17b103e3a2cfeee4bee6bc026","name":"https://git.kernel.org/stable/c/d9c537b14f4982f17b103e3a2cfeee4bee6bc026","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/becb89036a1320ef0a77da2d27935ac0704345c4","name":"https://git.kernel.org/stable/c/becb89036a1320ef0a77da2d27935ac0704345c4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/71c610aeb1770302ac9c9e0b9a4ecd37f1311928","name":"https://git.kernel.org/stable/c/71c610aeb1770302ac9c9e0b9a4ecd37f1311928","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6a5f5a5a32c78e67701f1d0f26bc87af68895604","name":"https://git.kernel.org/stable/c/6a5f5a5a32c78e67701f1d0f26bc87af68895604","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-97931","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97931","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 030a07e441296c372f946cd4065b5d831d8dc40c cbc1f954ce67d739d41d1f0757d29850353ebb6a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 030a07e441296c372f946cd4065b5d831d8dc40c becb89036a1320ef0a77da2d27935ac0704345c4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 030a07e441296c372f946cd4065b5d831d8dc40c 6a5f5a5a32c78e67701f1d0f26bc87af68895604 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 030a07e441296c372f946cd4065b5d831d8dc40c 938e8d6cee8d36f24669dfdcd3717e081eb32d64 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.222 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.189 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.158 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.111 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.53 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.7 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"97931","cve":"CVE-2026-97931","epss":"0.001450000","percentile":"0.032290000","score_date":"2026-10-05","updated_at":"2026-10-06 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the Linux kernel, the following vulnerability has been resolved:\n\nALSA: us122l: Prevent write upgrades for read mappings\n\nThe hwdep mmap callback rejects read-buffer mappings that are initially\nwritable, but leaves VM_MAYWRITE set on mappings created with PROT_READ.\nA process that can open the hwdep node O_RDWR can later use mprotect() to\nmake the mapping writable.\n\nThe read allocation begins with struct usb_stream. Its read_size member is\nused by the fault handler to decide which pages belong to the read buffer.\nThe read VMA intentionally remains expandable because pcm_usb_stream uses\nmremap() after reading that size. Changing read_size first can therefore\nmap and access pages beyond the allocation. The same member is also\nconsumed by usb_stream_free(), where changing it can make\nfree_pages_exact() release pages outside the allocation.\n\nClear VM_MAYWRITE for read-buffer mappings after rejecting an initially\nwritable VMA. This keeps the separate output-buffer mapping writable while\npreventing later permission upgrades."}],"metrics":[{"cvssV3_1":{"baseScore":7,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The bad data is written by a local process. It maps the us122l hwdep read buffer PROT_READ via usb_stream_hwdep_mmap(), upgrades it with mprotect() because VM_MAYWRITE was never cleared, and overwrites usb_stream.read_size. No remote protocol or USB packet carries the malicious value.\nAC:H - The driver only binds, and only creates /dev/snd/hwC*D*, when a TASCAM US-122L/US-144 is attached. A local attacker can't produce that hardware without physical access. Once it is present, mmap, mprotect, a read_size overwrite and mremap are fully deterministic.\nPR:L - The attacker needs an O_RDWR open of the hwdep node, which a normal user gets through audio group or seat uaccess ACLs. usb_stream_hwdep_open() and usb_stream_hwdep_ioctl() do no capability checks, and the stream already exists from probe.\nUI:N - The attacker's own process does the open, mmap, mprotect, write to read_size, mremap and page faults. No other user has to act.\nS:U - The result is corrupted kernel memory and local privilege escalation within the same kernel authority. No VM or hardware isolation boundary is crossed.\nC:H - With an inflated read_size, usb_stream_hwdep_vm_fault() maps virt_to_page((char *)s + offset) for offsets past the alloc_pages_exact() buffer. Userspace can then directly read arbitrary adjacent kernel pages.\nI:H - Those out-of-bounds pages are mapped writable into userspace, giving direct write access to kernel memory. In addition, usb_stream_free() calls free_pages_exact(s, read_size) with the tampered size, freeing pages that are still in use, a page-level use-after-free.\nA:H - Writing to foreign kernel pages, or freeing the wrong pages through usb_stream_free() on SET_PARAMS re-init or disconnect, corrupts the page allocator and kernel data, which leads to an oops or panic."}]}],"providerMetadata":{"dateUpdated":"2026-10-19T09:10:58.123Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/cbc1f954ce67d739d41d1f0757d29850353ebb6a"},{"url":"https://git.kernel.org/stable/c/becb89036a1320ef0a77da2d27935ac0704345c4"},{"url":"https://git.kernel.org/stable/c/6a5f5a5a32c78e67701f1d0f26bc87af68895604"},{"url":"https://git.kernel.org/stable/c/938e8d6cee8d36f24669dfdcd3717e081eb32d64"},{"url":"https://git.kernel.org/stable/c/64a87950239867682cde128020e1a47088295e5c"},{"url":"https://git.kernel.org/stable/c/d9c537b14f4982f17b103e3a2cfeee4bee6bc026"},{"url":"https://git.kernel.org/stable/c/0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f"},{"url":"https://git.kernel.org/stable/c/71c610aeb1770302ac9c9e0b9a4ecd37f1311928"}],"title":"ALSA: us122l: Prevent write upgrades for read mappings","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-97931","datePublished":"2026-09-25T10:22:47.382Z","dateReserved":"2026-09-25T10:18:58.203Z","dateUpdated":"2026-10-19T09:10:58.123Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-25 11:17:20","lastModifiedDate":"2026-10-19 10:17:43","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"97931","Ordinal":"1","Title":"ALSA: us122l: Prevent write upgrades for read mappings","CVE":"CVE-2026-97931","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"97931","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: us122l: Prevent write upgrades for read mappings\n\nThe hwdep mmap callback rejects read-buffer mappings that are initially\nwritable, but leaves VM_MAYWRITE set on mappings created with PROT_READ.\nA process that can open the hwdep node O_RDWR can later use mprotect() to\nmake the mapping writable.\n\nThe read allocation begins with struct usb_stream. Its read_size member is\nused by the fault handler to decide which pages belong to the read buffer.\nThe read VMA intentionally remains expandable because pcm_usb_stream uses\nmremap() after reading that size. Changing read_size first can therefore\nmap and access pages beyond the allocation. The same member is also\nconsumed by usb_stream_free(), where changing it can make\nfree_pages_exact() release pages outside the allocation.\n\nClear VM_MAYWRITE for read-buffer mappings after rejecting an initially\nwritable VMA. This keeps the separate output-buffer mapping writable while\npreventing later permission upgrades.","Type":"Description","Title":"ALSA: us122l: Prevent write upgrades for read mappings"}]}}}