{"id":"CVE-2026-64402","state":"PUBLISHED","title":"coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncoresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()\n\nWhen the SMB sink is used as a perf AUX sink, smb_update_buffer() calls\nsmb_sync_perf_buffer() to copy hardware trace data into the perf AUX ring\nbuffer pages. It derives pg_idx = head >> PAGE_SHIFT from @head, which is\nhandle->head, and indexes dst_pages[pg_idx]. The pg_idx %= nr_pages\nnormalization is only applied after the first loop iteration.\n\nThis leaves the initial page index underived from the buffer size, which\ncan result in an out-of-bounds write past dst_pages[] when head exceeds\nthe AUX buffer size.\n\nNormalize head modulo the AUX buffer size before deriving the page index\nand offset, mirroring tmc_etr_sync_perf_buffer().","publishedAt":"2026-07-25T08:50:45.075Z","updatedAt":"2026-08-17T04:55:00.113Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"38dbc8db8341ccdf8e1e1a067453d33ad751864b","versionType":"git"},{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"4c5a0a946373da99a80398289b28845b5ae40cd1","versionType":"git"},{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb","versionType":"git"},{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f","versionType":"git"},{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"98495b5a4d77dd22e106f462b76e1093a55b29a7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hwtracing/coresight/ultrasoc-smb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hwtracing/coresight/ultrasoc-smb.c"]}],"references":["https://git.kernel.org/stable/c/38dbc8db8341ccdf8e1e1a067453d33ad751864b","https://git.kernel.org/stable/c/4c5a0a946373da99a80398289b28845b5ae40cd1","https://git.kernel.org/stable/c/661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb","https://git.kernel.org/stable/c/daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f","https://git.kernel.org/stable/c/98495b5a4d77dd22e106f462b76e1093a55b29a7"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64402.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64402","state":"PUBLISHED","datePublished":"2026-07-25T08:50:45.075Z","dateUpdated":"2026-08-17T04:55:00.113Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.785Z"},"containers":{"cna":{"title":"coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncoresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()\n\nWhen the SMB sink is used as a perf AUX sink, smb_update_buffer() calls\nsmb_sync_perf_buffer() to copy hardware trace data into the perf AUX ring\nbuffer pages. It derives pg_idx = head >> PAGE_SHIFT from @head, which is\nhandle->head, and indexes dst_pages[pg_idx]. The pg_idx %= nr_pages\nnormalization is only applied after the first loop iteration.\n\nThis leaves the initial page index underived from the buffer size, which\ncan result in an out-of-bounds write past dst_pages[] when head exceeds\nthe AUX buffer size.\n\nNormalize head modulo the AUX buffer size before deriving the page index\nand offset, mirroring tmc_etr_sync_perf_buffer()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"38dbc8db8341ccdf8e1e1a067453d33ad751864b","versionType":"git"},{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"4c5a0a946373da99a80398289b28845b5ae40cd1","versionType":"git"},{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb","versionType":"git"},{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f","versionType":"git"},{"version":"06f5c2926aaa0fba7f99678da6ef77cbbbda1441","status":"affected","lessThan":"98495b5a4d77dd22e106f462b76e1093a55b29a7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hwtracing/coresight/ultrasoc-smb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hwtracing/coresight/ultrasoc-smb.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/38dbc8db8341ccdf8e1e1a067453d33ad751864b"},{"url":"https://git.kernel.org/stable/c/4c5a0a946373da99a80398289b28845b5ae40cd1"},{"url":"https://git.kernel.org/stable/c/661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb"},{"url":"https://git.kernel.org/stable/c/daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f"},{"url":"https://git.kernel.org/stable/c/98495b5a4d77dd22e106f462b76e1093a55b29a7"}],"metrics":[{"cvssV3_1":{"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"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable path is reached locally through perf_event_open(), AUX-buffer mmap, and perf event scheduling or ioctls; it has no network or physical entry point.\nAC:L - An attacker can choose a small AUX buffer, advance aux_tail, and repeatedly stop and restart their own trace until the monotonically increasing head crosses the buffer size. No race or condition outside the attacker's control is required.\nPR:L - A self-targeted event with exclude_kernel=1 is available to an ordinary unprivileged user under the mainline default perf_event_paranoid setting, and selecting the SMB sink requires no privileged sysfs write.\nUI:N - The attacker creates, runs, consumes, and stops their own tracing event without any victim action.\nS:U - Exploitation compromises the host kernel within the same security authority and does not inherently cross a VM, IOMMU, or other separate security boundary.\nC:H - The out-of-range page-pointer lookup directs memcpy() through a pointer obtained from groomable adjacent kernel memory. Resulting kernel-memory corruption can plausibly enable control-flow hijacking and unrestricted disclosure.\nI:H - The attacker-influenced trace data is written through an invalid kernel pointer, providing exploitable memory corruption that can plausibly yield arbitrary kernel modification or code execution.\nA:H - An ungroomed invalid destination pointer can immediately cause a kernel oops or panic, and the attacker can trigger the path repeatedly."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:55:00.113Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}