CVE-2026-89747

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89747", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.762Z", "datePublished": "2026-09-11T19:46:52.268Z", "dateUpdated": "2026-10-19T08:52:01.177Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:52:01.177Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free in trace_pipe read on sub-buffer order change\n\nWriting to buffer_subbuf_size_kb calls ring_buffer_subbuf_order_set(),\nwhich frees every sub-buffer of the ring buffer, including the reader\npage, and replaces them with newly allocated ones.\n\nReaders of trace_pipe hold pointers into those pages. ring_buffer_peek()\nlooks up an event under cpu_buffer->reader_lock but returns the event\npointer after dropping the lock, and peek_next_entry() then calls\nring_buffer_event_length() and ring_buffer_event_data() on it. If the\nsub-buffer order is changed in that window, the reader dereferences\nfreed memory:\n\n BUG: KASAN: use-after-free in ring_buffer_peek+0x3e0/0x430\n Read of size 1 at addr ffff88802a4cf010 by task syz-executor989/6002\n\n Freed by:\n free_buffer_page kernel/trace/ring_buffer.c:398 [inline]\n ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444\n buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221\n\nTake trace_access_lock(RING_BUFFER_ALL_CPUS) around the order change.\nThis is the lock trace_pipe readers already hold across their entire\npeek-and-print loop, so the swap can no longer race with a reader that\nis dereferencing a peeked event."}], "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 UAF is reached only via local tracefs: write() to buffer_subbuf_size_kb (buffer_subbuf_size_write -> ring_buffer_subbuf_order_set) racing with read()/splice() of trace_pipe (tracing_read_pipe -> ring_buffer_peek). No network, adjacent-radio, or physical-device path reaches this code.\nAC:L - The attacker controls both sides of the race: one thread reads trace_pipe while another writes buffer_subbuf_size_kb, which frees the reader page after dropping reader_lock. ring_buffer_peek then dereferences the stale event pointer; the attempt is retryable at will and CONFIG_TRACING is standard.\nPR:L - tracing_check_open_get_tr() checks only LOCKDOWN_TRACEFS and DAC, with no capable() gate. buffer_subbuf_size_kb (0640) and trace_pipe (0440) are delegated via uid=/gid= mounts to tracing-group accounts on Android/Perfetto, ChromeOS, and developer systems, matching CVE-2025-38101 and CVE-2026-74634.\nUI:N - The attacker opens and reads their own trace_pipe and writes buffer_subbuf_size_kb from their own threads. No victim action, mount, or file open by another user is required.\nS:U - The use-after-free corrupts kernel ring-buffer pages and metadata inside the host kernel's security authority. It can yield local privilege escalation but does not cross a VM, IOMMU, container, or hardware trust boundary.\nC:H - ring_buffer_subbuf_order_set() frees reader-page sub-buffers while ring_buffer_peek() still holds a pointer into them; peek_next_entry() and print_trace_line() then read the freed event and copy it to userspace via trace_pipe, disclosing recycled kernel heap contents.\nI:H - Freed sub-buffer pages and buffer_page objects can be reallocated while the reader still consumes attacker-controlled type_len/payload and print_trace_line() dispatches on iter->ent->type. This UAF heap corruption is exploitable for arbitrary kernel writes and control-flow hijack.\nA:H - Dereferencing the freed reader page in ring_buffer_peek()/ring_buffer_event_length() causes a kernel oops, which is the syzbot KASAN use-after-free. The attacker can retrigger that crash 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/trace.c"], "versions": [{"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "lessThan": "05ebe1e1d7d38c2612bacfefe043a33572ae34cb", "status": "affected", "versionType": "git"}, {"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "lessThan": "ddbe921ed16a0ad2d9e09574c3f3aabec7528325", "status": "affected", "versionType": "git"}, {"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "lessThan": "7a49d19ff9baaf61217e5ec14199c18bc2d93ee4", "status": "affected", "versionType": "git"}, {"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "lessThan": "372f8534244d632ad5118e8a87a11291b01712d3", "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/trace.c"], "versions": [{"version": "6.8", "status": "affected"}, {"version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "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": "6.12.109"}, {"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/05ebe1e1d7d38c2612bacfefe043a33572ae34cb"}, {"url": "https://git.kernel.org/stable/c/ddbe921ed16a0ad2d9e09574c3f3aabec7528325"}, {"url": "https://git.kernel.org/stable/c/7a49d19ff9baaf61217e5ec14199c18bc2d93ee4"}, {"url": "https://git.kernel.org/stable/c/372f8534244d632ad5118e8a87a11291b01712d3"}], "title": "tracing: Fix use-after-free in trace_pipe read on sub-buffer order change", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["kernel/trace/trace.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "05ebe1e1d7d38c2612bacfefe043a33572ae34cb", "status": "affected", "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "versionType": "git"}, {"lessThan": "ddbe921ed16a0ad2d9e09574c3f3aabec7528325", "status": "affected", "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "versionType": "git"}, {"lessThan": "7a49d19ff9baaf61217e5ec14199c18bc2d93ee4", "status": "affected", "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "versionType": "git"}, {"lessThan": "372f8534244d632ad5118e8a87a11291b01712d3", "status": "affected", "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["kernel/trace/trace.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.8"}, {"lessThan": "6.8", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.109", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free in trace_pipe read on sub-buffer order change\n\nWriting to buffer_subbuf_size_kb calls ring_buffer_subbuf_order_set(),\nwhich frees every sub-buffer of the ring buffer, including the reader\npage, and replaces them with newly allocated ones.\n\nReaders of trace_pipe hold pointers into those pages. ring_buffer_peek()\nlooks up an event under cpu_buffer->reader_lock but returns the event\npointer after dropping the lock, and peek_next_entry() then calls\nring_buffer_event_length() and ring_buffer_event_data() on it. If the\nsub-buffer order is changed in that window, the reader dereferences\nfreed memory:\n\n BUG: KASAN: use-after-free in ring_buffer_peek+0x3e0/0x430\n Read of size 1 at addr ffff88802a4cf010 by task syz-executor989/6002\n\n Freed by:\n free_buffer_page kernel/trace/ring_buffer.c:398 [inline]\n ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444\n buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221\n\nTake trace_access_lock(RING_BUFFER_ALL_CPUS) around the order change.\nThis is the lock trace_pipe readers already hold across their entire\npeek-and-print loop, so the swap can no longer race with a reader that\nis dereferencing a peeked event."}], "id": "CVE-2026-89747", "lastModified": "2026-10-19T09:18:17.650", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-11T20:20:05.517", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/05ebe1e1d7d38c2612bacfefe043a33572ae34cb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/372f8534244d632ad5118e8a87a11291b01712d3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7a49d19ff9baaf61217e5ec14199c18bc2d93ee4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ddbe921ed16a0ad2d9e09574c3f3aabec7528325"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel tracing: Use-after-free vulnerability during trace_pipe read", "id": "2532358", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532358"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.1", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["A flaw was found in the Linux kernel's tracing component. A local attacker could exploit a use-after-free vulnerability, a type of memory corruption, by manipulating the `trace_pipe` functionality. This occurs when the system attempts to read from memory that has already been released, leading to unpredictable behavior. Successful exploitation could result in system instability or a denial of service."], "name": "CVE-2026-89747", "public_date": "2026-09-11T19:46:52Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89747\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89747\nhttps://git.kernel.org/stable/c/05ebe1e1d7d38c2612bacfefe043a33572ae34cb\nhttps://git.kernel.org/stable/c/372f8534244d632ad5118e8a87a11291b01712d3\nhttps://git.kernel.org/stable/c/7a49d19ff9baaf61217e5ec14199c18bc2d93ee4\nhttps://git.kernel.org/stable/c/ddbe921ed16a0ad2d9e09574c3f3aabec7528325"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f9b94daa542a8d2532f0930f01cd9aec2d19621b,05ebe1e1d7d38c2612bacfefe043a33572ae34cb)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f9b94daa542a8d2532f0930f01cd9aec2d19621b,ddbe921ed16a0ad2d9e09574c3f3aabec7528325)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f9b94daa542a8d2532f0930f01cd9aec2d19621b,7a49d19ff9baaf61217e5ec14199c18bc2d93ee4)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f9b94daa542a8d2532f0930f01cd9aec2d19621b,372f8534244d632ad5118e8a87a11291b01712d3)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.8"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.8)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.109,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.50,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.4,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-12T06:00:11.706007+00:00", "updated": "2026-09-15T19:15:16.163610+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}