{"id":"CVE-2026-89503","title":"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 reade…","summary":"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 reade…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-367"],"vendor":"Linux","product":"Linux","affected":["Linux >= bce761d757452ba5eb77e11fecc37a04b67494e7 < 2313ff69bd237aad264a5913907f374f958335a2","Linux >= bce761d757452ba5eb77e11fecc37a04b67494e7 < 2dc510957fe8fd098ab3c3147ebdf34d00cd2734","Linux >= bce761d757452ba5eb77e11fecc37a04b67494e7 < 53106e9262a310ef2c9a9321168c03705940c678","Linux >= bce761d757452ba5eb77e11fecc37a04b67494e7 < e743527c5bfdceda1095bc0a9e596e2aebb6a9c3","Linux 6.8"],"published":"2026-09-11","updated":"2026-10-03","sourceUpdated":"2026-10-03T11:17:42.583","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89503","references":[{"url":"https://git.kernel.org/stable/c/2313ff69bd237aad264a5913907f374f958335a2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2dc510957fe8fd098ab3c3147ebdf34d00cd2734","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/53106e9262a310ef2c9a9321168c03705940c678","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e743527c5bfdceda1095bc0a9e596e2aebb6a9c3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89503.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89503"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532017"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89503"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89503"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89503.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00168,"epssPercentile":0.06064,"scores":{"nvd":7.8,"vendor":5.5,"cna":7.8},"ingestedAt":"2026-09-14T15:23:07.475Z","slug":"CVE-2026-89503","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89503.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":215298,"id":"CVE-2026-89503","ts":1791027882952,"field":"cvss","old":"5.5","new":"7.8"},{"seq":215297,"id":"CVE-2026-89503","ts":1791027882952,"field":"severity","old":"medium","new":"high"},{"seq":202807,"id":"CVE-2026-89503","ts":1789403724828,"field":"cvss","old":"7.8","new":"5.5"},{"seq":202806,"id":"CVE-2026-89503","ts":1789403724828,"field":"severity","old":"high","new":"medium"},{"seq":197990,"id":"CVE-2026-89503","ts":1789384321278,"field":"cvss","old":"5.5","new":"7.8"},{"seq":197989,"id":"CVE-2026-89503","ts":1789384321278,"field":"severity","old":"medium","new":"high"},{"seq":183504,"id":"CVE-2026-89503","ts":1789356675640,"field":"cvss","old":"7.8","new":"5.5"},{"seq":183503,"id":"CVE-2026-89503","ts":1789356675640,"field":"severity","old":"high","new":"medium"},{"seq":153294,"id":"CVE-2026-89503","ts":1789285349921,"field":"cvss","old":null,"new":"7.8"},{"seq":153293,"id":"CVE-2026-89503","ts":1789285349921,"field":"severity","old":"none","new":"high"},{"seq":109622,"id":"CVE-2026-89503","ts":1789183732683,"field":"cvss","old":null,"new":"5.5"},{"seq":109621,"id":"CVE-2026-89503","ts":1789183732683,"field":"severity","old":"none","new":"medium"}]}