{"id":"CVE-2026-89657","title":"libceph: validate OSD extent maps before cursor advance","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: validate OSD extent maps before cursor advance\n\nnet/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read\ndata length matches the summed extent le…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-125"],"vendor":"Linux","product":"Linux","affected":["Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 94ae5145c520618802b0a24c047dcd5f05835db8","Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 058ffa81f9440c5b4714685611cf697fd3739ec9","Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 2571b35883268a266554e80d368e67fdfea7fb9d","Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 201db408872ca12cf09e36bf0f560138c3dcfa1c","Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 9ec08b7499a62c6d4afa93d36ab47a43fcad57d1","Linux 6.6"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:50:28.836Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89657","references":[{"url":"https://git.kernel.org/stable/c/94ae5145c520618802b0a24c047dcd5f05835db8"},{"url":"https://git.kernel.org/stable/c/058ffa81f9440c5b4714685611cf697fd3739ec9"},{"url":"https://git.kernel.org/stable/c/2571b35883268a266554e80d368e67fdfea7fb9d"},{"url":"https://git.kernel.org/stable/c/201db408872ca12cf09e36bf0f560138c3dcfa1c"},{"url":"https://git.kernel.org/stable/c/9ec08b7499a62c6d4afa93d36ab47a43fcad57d1"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89657.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89657"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532301"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89657"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89657"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89657.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00612,"epssPercentile":0.49084,"scores":{"cna":7.5,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.450Z","slug":"CVE-2026-89657","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: validate OSD extent maps before cursor advance\n\nnet/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read\ndata length matches the summed extent lengths, but it does not validate\nthat each OSD-supplied extent is monotonic and lies inside the original\nrequest range. A malformed authenticated OSD reply can advertise a\nfar-forward nonzero extent offset with a matching data length and make\nthe client advance the message-data cursor beyond the request buffer.\nThis reaches the BUG_ON(!*length) assertion in ceph_msg_data_next() from\nthe client receive path.\n\nImpact: A malicious or compromised authenticated Ceph OSD peer can crash\na kernel Ceph client via a malformed sparse-read reply.\n\nReject sparse extent maps that overflow, move backwards, overlap, or\nextend outside the original sparse-read request before advancing the\ncursor.\n\n[ idryomov: perform sparse_extent_map_valid() check a bit earlier,\n  in CEPH_SPARSE_READ_DATA_LEN instead of CEPH_SPARSE_READ_DATA_PRE\n  state ]\n\n## Affected\n\n- `Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 94ae5145c520618802b0a24c047dcd5f05835db8`\n- `Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 058ffa81f9440c5b4714685611cf697fd3739ec9`\n- `Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 2571b35883268a266554e80d368e67fdfea7fb9d`\n- `Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 201db408872ca12cf09e36bf0f560138c3dcfa1c`\n- `Linux >= f628d799972799023d32c2542bb2639eb8c4f84e < 9ec08b7499a62c6d4afa93d36ab47a43fcad57d1`\n- `Linux 6.6`\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, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89657.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":224642,"id":"CVE-2026-89657","ts":1792401451689,"field":"cvss","old":"7","new":"7.5"},{"seq":208086,"id":"CVE-2026-89657","ts":1789922706880,"field":"cvss","old":"7.5","new":"7"},{"seq":197787,"id":"CVE-2026-89657","ts":1789384318853,"field":"cvss","old":"5.3","new":"7.5"},{"seq":197786,"id":"CVE-2026-89657","ts":1789384318853,"field":"severity","old":"medium","new":"high"},{"seq":183711,"id":"CVE-2026-89657","ts":1789356677059,"field":"cvss","old":"7.5","new":"5.3"},{"seq":183710,"id":"CVE-2026-89657","ts":1789356677059,"field":"severity","old":"high","new":"medium"},{"seq":153512,"id":"CVE-2026-89657","ts":1789285351093,"field":"cvss","old":null,"new":"7.5"},{"seq":153511,"id":"CVE-2026-89657","ts":1789285351093,"field":"severity","old":"none","new":"high"},{"seq":147404,"id":"CVE-2026-89657","ts":1789270210778,"field":"cvss","old":null,"new":"5.3"},{"seq":147403,"id":"CVE-2026-89657","ts":1789270210778,"field":"severity","old":"none","new":"medium"},{"seq":109156,"id":"CVE-2026-89657","ts":1789183730532,"field":"cvss","old":null,"new":"5.3"},{"seq":109155,"id":"CVE-2026-89657","ts":1789183730532,"field":"severity","old":"none","new":"medium"}]}