CVE-2026-74634

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74634", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.922Z", "datePublished": "2026-08-22T15:32:14.547Z", "dateUpdated": "2026-08-25T05:40:58.185Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-25T05:40:58.185Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Prevent subbuf order change when resizing is disabled\n\nBecause ring_buffer_subbuf_order_set() frees buffer pages, we can't\nallow it when resizing is disabled. A non-consuming reader is at risk of\nuse-after-free (rb_advance_iter()).\n\nReturn -EBUSY on resize_disabled, matching ring_buffer_resize()\nbehaviour."}], "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 operations: write() to buffer_subbuf_size_kb (buffer_subbuf_size_write) while a non-consuming ring_buffer_read_start() iterator is active from reading trace/per_cpu/cpuN/trace. No network, adjacent-radio, or physical-device path reaches ring_buffer_subbuf_order_set().\nAC:L - The attacker controls both sides: one thread holds trace open for read (sets resize_disabled via ring_buffer_read_start) while another writes buffer_subbuf_size_kb to free pages still referenced by iter->head_page. rb_advance_iter()/rb_inc_iter then dereferences freed memory; the race is reliably retried.\nPR:L - tracing_check_open_get_tr() enforces only LOCKDOWN_TRACEFS and DAC with no capability check. tracefs buffer_subbuf_size_kb and trace are mode 0640 and are routinely delegated via gid=/mode= to tracing-group members on Android/Perfetto, ChromeOS, and developer systems, matching prior CNA tracefs UAF scores (CVE-2024-50207, CVE-2025-38101).\nUI:N - Exploitation uses the attacker's own tracefs file descriptors and threads (open trace for read, write buffer_subbuf_size_kb). No separate victim mount, click, or configuration action is required beyond the attacker holding tracefs access.\nS:U - The use-after-free corrupts kernel ring-buffer heap pages and metadata within the same OS security authority. It enables local privilege escalation but does not cross VM, IOMMU, container, or hardware trust boundaries.\nC:H - ring_buffer_subbuf_order_set() frees buffer_page data pages while iterators retain head_page pointers; rb_iter_head_event() memcpy() and rb_inc_iter() read iter->head_page->page after free_pages(), leaking recycled kernel heap contents to userspace through trace reads.\nI:H - Freed sub-buffer pages and buffer_page structures can be reused while iterators and splice paths still perform stores and list operations on them. This UAF heap corruption is exploitable for arbitrary kernel writes and control-flow hijack, not merely a crash.\nA:H - Concurrent page frees with active iterators corrupt ring-buffer lists and cause use-after-free dereferences in rb_advance_iter(), producing kernel oopses/panics. syzbot reported this failure mode and the attacker can retrigger it 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": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "lessThan": "b45b91db41379ee5fb36c187d6d7c37b725cbe8e", "status": "affected", "versionType": "git"}, {"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "lessThan": "62978cf6347972c04130e4e841ba404504d92b32", "status": "affected", "versionType": "git"}, {"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "lessThan": "7568e9e717e7540bd05bcc007f5d76fcaff3cdff", "status": "affected", "versionType": "git"}, {"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "lessThan": "bf98d7b0d5a99991e47e66cee4eb1d3fa514be97", "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": "6.12.104", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "6.12.104"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18.45"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.1.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/b45b91db41379ee5fb36c187d6d7c37b725cbe8e"}, {"url": "https://git.kernel.org/stable/c/62978cf6347972c04130e4e841ba404504d92b32"}, {"url": "https://git.kernel.org/stable/c/7568e9e717e7540bd05bcc007f5d76fcaff3cdff"}, {"url": "https://git.kernel.org/stable/c/bf98d7b0d5a99991e47e66cee4eb1d3fa514be97"}], "title": "ring-buffer: Prevent subbuf order change when resizing is disabled", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["kernel/trace/ring_buffer.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "b45b91db41379ee5fb36c187d6d7c37b725cbe8e", "status": "affected", "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "versionType": "git"}, {"lessThan": "62978cf6347972c04130e4e841ba404504d92b32", "status": "affected", "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "versionType": "git"}, {"lessThan": "7568e9e717e7540bd05bcc007f5d76fcaff3cdff", "status": "affected", "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "versionType": "git"}, {"lessThan": "bf98d7b0d5a99991e47e66cee4eb1d3fa514be97", "status": "affected", "version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["kernel/trace/ring_buffer.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": "6.12.104", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.45", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "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\nring-buffer: Prevent subbuf order change when resizing is disabled\n\nBecause ring_buffer_subbuf_order_set() frees buffer pages, we can't\nallow it when resizing is disabled. A non-consuming reader is at risk of\nuse-after-free (rb_advance_iter()).\n\nReturn -EBUSY on resize_disabled, matching ring_buffer_resize()\nbehaviour."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nring-buffer: Evitar el cambio de orden de subbuf cuando el redimensionamiento est\u00e1 deshabilitado\n\nDebido a que ring_buffer_subbuf_order_set() libera p\u00e1ginas de b\u00fafer, no podemos permitirlo cuando el redimensionamiento est\u00e1 deshabilitado. Un lector no consumidor est\u00e1 en riesgo de uso despu\u00e9s de liberaci\u00f3n (rb_advance_iter()).\n\nDevolver -EBUSY en caso de resize_disabled, coincidiendo con el comportamiento de ring_buffer_resize()."}], "id": "CVE-2026-74634", "lastModified": "2026-10-14T13:10:00.187", "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": "2026-08-22T16:16:36.487", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/62978cf6347972c04130e4e841ba404504d92b32"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7568e9e717e7540bd05bcc007f5d76fcaff3cdff"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b45b91db41379ee5fb36c187d6d7c37b725cbe8e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bf98d7b0d5a99991e47e66cee4eb1d3fa514be97"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ring-buffer: Prevent subbuf order change when resizing is disabled", "id": "2521460", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2521460"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nring-buffer: Prevent subbuf order change when resizing is disabled\nBecause ring_buffer_subbuf_order_set() frees buffer pages, we can't\nallow it when resizing is disabled. A non-consuming reader is at risk of\nuse-after-free (rb_advance_iter()).\nReturn -EBUSY on resize_disabled, matching ring_buffer_resize()\nbehaviour.", "A flaw was found in the Linux kernel's ring-buffer component. This vulnerability occurs when the system attempts to change the order of sub-buffers while resizing is disabled, leading to memory being freed prematurely. A local attacker could exploit this use-after-free condition to potentially cause a system crash (denial of service) or gain elevated privileges."], "name": "CVE-2026-74634", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-22T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74634\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74634\nhttps://lore.kernel.org/linux-cve-announce/2026082222-CVE-2026-74634-71a0@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f9b94daa542a8d2532f0930f01cd9aec2d19621b,b45b91db41379ee5fb36c187d6d7c37b725cbe8e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f9b94daa542a8d2532f0930f01cd9aec2d19621b,62978cf6347972c04130e4e841ba404504d92b32)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f9b94daa542a8d2532f0930f01cd9aec2d19621b,7568e9e717e7540bd05bcc007f5d76fcaff3cdff)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f9b94daa542a8d2532f0930f01cd9aec2d19621b,bf98d7b0d5a99991e47e66cee4eb1d3fa514be97)"}}], "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": "[6.8,6.8]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.8)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.12.104,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.45,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1.9,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2,*]"}}], "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": "2026-08-22T17:15:04.454791+00:00", "updated": "2026-08-25T13:45:04.366542+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-416", "CWE-825"]}