{"id":"CVE-2026-89653","title":"kernel: ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode (CVE-2026-89653)","summary":"A flaw was found in the Linux kernel's Ceph filesystem. This vulnerability occurs when a malicious or malformed MDSMap export_targets entry, controlled by a monitor, contains a rank value that exceeds the maximum allowed (CEPH_MAX_MDS) dur…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"vendor","cwe":"CWE-787","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 8","enterprise_linux 9","openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-16","sourceUpdated":"2026-09-16T20:41:51+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89653.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89653.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89653"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532386"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89653"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89653"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89653.mbox"},{"url":"https://git.kernel.org/stable/c/3740c88ca9cb2210a8dbdd55ea4cec119fbe86fe"},{"url":"https://git.kernel.org/stable/c/8c823bbab3c24e657469a84db96902ba82d4e8bb"},{"url":"https://git.kernel.org/stable/c/c4addccd05bacbef2144b4db14853d0308a218ac"},{"url":"https://git.kernel.org/stable/c/736adee11af36e407ed902264f8b2fb5cf94b62f"},{"url":"https://git.kernel.org/stable/c/4d298880f82c42383b36946bafde7ccf4d804c9b"},{"url":"https://git.kernel.org/stable/c/96c3f5fbb0d5386e7111426f047f98cec4586674"},{"url":"https://git.kernel.org/stable/c/aedc9053d909508a5f56c3f49f885fc030df4730"}],"tags":["csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00509,"epssPercentile":0.42294,"scores":{"vendor":7,"cna":9.8},"ingestedAt":"2026-09-14T15:23:07.450Z","slug":"CVE-2026-89653","body":"## Overview\n\nA flaw was found in the Linux kernel's Ceph filesystem. This vulnerability occurs when a malicious or malformed MDSMap export_targets entry, controlled by a monitor, contains a rank value that exceeds the maximum allowed (CEPH_MAX_MDS) during the decoding process. This can lead to an out-of-bounds write, where the system attempts to write data beyond its designated memory area. Such an issue could result in a denial of service (DoS), making the system unresponsive or unstable.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89653.json)\n\n**kernel: ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode** — rated Important by Red Hat. Released 2026-09-11, updated 2026-09-16.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\nNot affected:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 7\n\n## Remediation\n\nAffected","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":44.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":206390,"id":"CVE-2026-89653","ts":1789663224293,"field":"cvss","old":"7","new":"8.1"},{"seq":205433,"id":"CVE-2026-89653","ts":1789576712324,"field":"cvss","old":"9.8","new":"7"},{"seq":205432,"id":"CVE-2026-89653","ts":1789576712324,"field":"severity","old":"critical","new":"high"},{"seq":197791,"id":"CVE-2026-89653","ts":1789384318871,"field":"cvss","old":"7.5","new":"9.8"},{"seq":197790,"id":"CVE-2026-89653","ts":1789384318871,"field":"severity","old":"high","new":"critical"},{"seq":183373,"id":"CVE-2026-89653","ts":1789356675094,"field":"cvss","old":"9.8","new":"7.5"},{"seq":183372,"id":"CVE-2026-89653","ts":1789356675094,"field":"severity","old":"critical","new":"high"},{"seq":153504,"id":"CVE-2026-89653","ts":1789285350950,"field":"cvss","old":null,"new":"9.8"},{"seq":153503,"id":"CVE-2026-89653","ts":1789285350950,"field":"severity","old":"none","new":"critical"},{"seq":147273,"id":"CVE-2026-89653","ts":1789270206116,"field":"cvss","old":null,"new":"7.5"},{"seq":147272,"id":"CVE-2026-89653","ts":1789270206116,"field":"severity","old":"none","new":"high"},{"seq":109030,"id":"CVE-2026-89653","ts":1789183730029,"field":"cvss","old":null,"new":"7.5"},{"seq":109029,"id":"CVE-2026-89653","ts":1789183730029,"field":"severity","old":"none","new":"high"}]}