{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89503", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.715Z", "datePublished": "2026-09-11T19:43:51.357Z", "dateUpdated": "2026-10-19T08:47:54.761Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:47:54.761Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()\n\nring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set,\nit can allocate a reader page with an outdated order. This isn't a big\nissue, the user can still re-allocate a new reader page and try again.\n\nHowever, what is more problematic is if the value of subbuf_order\nchanges in the middle of ring_buffer_alloc_read_page(). In that case,\nbpage->order might not match the actual allocated memory.\n\nUse bpage->order for the allocation to prevent this race." } ], "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 bug is reached only via local tracefs: read() on per_cpu/*/trace_pipe_raw or snapshot_raw (tracing_buffers_read -> ring_buffer_alloc_read_page) racing with write() to buffer_subbuf_size_kb. No network, adjacent-radio, or physical path reaches this code.\nAC:L - The attacker controls both sides: one thread reads trace_pipe_raw while another writes buffer_subbuf_size_kb. GFP_KERNEL in alloc_cpu_data sleeps, so subbuf_order can change between the two reads in ring_buffer_alloc_read_page(); the race is reliably retried.\nPR:L - tracing_check_open_get_tr() enforces only LOCKDOWN_TRACEFS and DAC with no capable() check. trace_pipe_raw is 0440 and buffer_subbuf_size_kb is 0640, routinely delegated via gid=/mode= to tracing-group members on Android/Perfetto, ChromeOS, and developer systems.\nUI:N - Exploitation uses the attacker's own tracefs file descriptors and threads. No separate victim mount, click, or configuration action is required beyond the attacker holding tracefs access.\nS:U - Wrong-order page allocation and free corrupt the kernel buddy allocator and ring-buffer pages within the same OS security authority. This enables local privilege escalation but does not cross VM, IOMMU, or hardware trust boundaries.\nC:H - When bpage->order does not match the alloc_pages() size, later copy_to_user of a stale page_size and ring_buffer_read_page memcpy/memset over-read adjacent kernel pages, and wrong-order free_pages() corrupts the buddy allocator, yielding arbitrary kernel reads.\nI:H - free_pages() with a larger order than allocated, or memcpy/memset into an undersized sub-buffer when reader_page->order later matches the stale bpage->order, corrupts adjacent pages and the buddy allocator, which is exploitable for arbitrary kernel writes.\nA:H - Wrong-order free_pages() and out-of-bounds writes on undersized compound pages crash the kernel via buddy-allocator corruption or oops in ring_buffer_read_page/free_read_page. The attacker can retrigger the race at will." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/ring_buffer.c" ], "versions": [ { "version": "bce761d757452ba5eb77e11fecc37a04b67494e7", "lessThan": "2313ff69bd237aad264a5913907f374f958335a2", "status": "affected", "versionType": "git" }, { "version": "bce761d757452ba5eb77e11fecc37a04b67494e7", "lessThan": "2dc510957fe8fd098ab3c3147ebdf34d00cd2734", "status": "affected", "versionType": "git" }, { "version": "bce761d757452ba5eb77e11fecc37a04b67494e7", "lessThan": "53106e9262a310ef2c9a9321168c03705940c678", "status": "affected", "versionType": "git" }, { "version": "bce761d757452ba5eb77e11fecc37a04b67494e7", "lessThan": "e743527c5bfdceda1095bc0a9e596e2aebb6a9c3", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/ring_buffer.c" ], "versions": [ { "version": "6.8", "status": "affected" }, { "version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2313ff69bd237aad264a5913907f374f958335a2" }, { "url": "https://git.kernel.org/stable/c/2dc510957fe8fd098ab3c3147ebdf34d00cd2734" }, { "url": "https://git.kernel.org/stable/c/53106e9262a310ef2c9a9321168c03705940c678" }, { "url": "https://git.kernel.org/stable/c/e743527c5bfdceda1095bc0a9e596e2aebb6a9c3" } ], "title": "ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page()", "x_generator": { "engine": "bippy-1.2.0" } } } }