{"id":"CVE-2026-89657","summary":"libceph: validate OSD extent maps before cursor advance","details":"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 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 ]","modified":"2026-09-13T03:47:20.176098057Z","published":"2026-09-11T19:45:46.118Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89657.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/058ffa81f9440c5b4714685611cf697fd3739ec9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/201db408872ca12cf09e36bf0f560138c3dcfa1c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2571b35883268a266554e80d368e67fdfea7fb9d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9ec08b7499a62c6d4afa93d36ab47a43fcad57d1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89657.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89657"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f628d799972799023d32c2542bb2639eb8c4f84e"},{"fixed":"058ffa81f9440c5b4714685611cf697fd3739ec9"},{"fixed":"2571b35883268a266554e80d368e67fdfea7fb9d"},{"fixed":"201db408872ca12cf09e36bf0f560138c3dcfa1c"},{"fixed":"9ec08b7499a62c6d4afa93d36ab47a43fcad57d1"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89657.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.6.0"},{"fixed":"6.12.109"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.50"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89657.json"}}],"schema_version":"1.9.0"}