{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89650", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.742Z", "datePublished": "2026-09-11T19:45:40.867Z", "dateUpdated": "2026-10-19T08:50:21.912Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:50:21.912Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: bound num_export_targets array for mds info v2/v3\n\nceph_mdsmap_decode() in fs/ceph/mdsmap.c reads num_export_targets from\neach per-mds info record and advances the decode cursor by\nnum_export_targets * sizeof(u32) without first checking that many bytes\nremain. The only upper-bound check that catches a runaway cursor\n(*p > info_end) is gated on info_v >= 4, because info_end is left NULL\nfor info_v 2 and 3. When the monitor sends an MDS map whose per-mds\ninfo version is 2 or 3 with an oversized num_export_targets, the cursor\nmoves past the message front buffer and the later export-targets loop\ncalls the unchecked ceph_decode_32() on out-of-bounds memory.\n\nA kernel client processes CEPH_MSG_MDS_MAP from its monitor session\n(net/ceph/mon_client.c dispatches it; fs/ceph/super.c routes it to\nceph_mdsc_handle_mdsmap(), which sets end to the front buffer bound and\ncalls ceph_mdsmap_decode()). A malicious or compromised monitor, or an\non-path attacker on an unsigned/unencrypted messenger session, can\ntherefore drive an out-of-bounds read in the client kernel; on x86_64\nwith KASAN it is reported as a slab-out-of-bounds read in\nceph_mdsmap_decode(). The decoded values land in the internal\ninfo->export_targets[] array, so the consequence is a kernel\nout-of-bounds read, not an information leak to the attacker.\n\nImpact: a malicious or compromised Ceph monitor sending an MDS map with\na per-mds info version of 2 or 3 and an oversized num_export_targets\nfield triggers an out-of-bounds read in the CephFS client kernel.\n\nAdd a ceph_decode_need() for the export-targets array before advancing\nthe cursor, so the bound is enforced for every info_v >= 2, not only\ninfo_v >= 4. This mirrors the count-then-need idiom already used for\nm_data_pg_pools later in the same function.\n\nCompute the export-targets byte count with size_mul() and reuse that\nchecked length when advancing the cursor, so the attacker-controlled\nnum_export_targets multiplication fails closed on overflow rather than\nrelying on the later kcalloc() guard." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - CEPH_MSG_MDS_MAP arrives over the kernel Ceph messenger TCP session from a monitor (mon_dispatch/extra_mon_dispatch) or MDS (mds_dispatch) and is decoded in ceph_mdsmap_decode(); a malicious cluster peer or on-path attacker on an unsigned msgr session reaches the bug with network data alone.\nAC:L - The attacker fully controls per-mds info_v and num_export_targets; setting info_v to 2 or 3 (so info_end stays NULL) and an oversized count deterministically advances the cursor past msg->front and hits unchecked ceph_decode_32(), with no race or victim memory layout required.\nPR:N - The attacker acts as the remote Ceph monitor or MDS peer (or MITM on msgr1/crc or auth_none); no local account, capability, or privilege on the victim CephFS client host is required.\nUI:N - Once CephFS is mounted, the kernel client subscribes to MDS maps and ceph_mdsc_handle_mdsmap() runs automatically on each update; no further mount, open, or interactive victim action is required at exploit time.\nS:U - The out-of-bounds read, any leaked heap bytes, and a possible oops stay inside the victim host kernel CephFS client and do not cross a VM, container, IOMMU, or other security authority.\nC:H - An attacker-chosen num_export_targets drives an unbounded loop of unchecked ceph_decode_32() reads past the message front slab into adjacent kernel heap (KASAN slab-out-of-bounds); per kernel guidance an unbounded out-of-bounds read is Confidentiality High.\nI:N - OOB words are copied only into a correctly sized kcalloc'd export_targets array; overshooting the front buffer then fails later ceph_decode_32_safe() so the map is destroyed and never installed, giving no out-of-bounds write or control-flow primitive.\nA:H - Walking an attacker-chosen number of u32s past the kmalloc'd msg->front object into unmapped or guarded pages oopses the ceph-msgr worker, and a failed decode also shuts down the mount via ceph_umount_begin(); both are repeatable on each crafted map." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/ceph/mdsmap.c" ], "versions": [ { "version": "d463a43d69f4af85887671d76182437775fd1631", "lessThan": "0c4bcc3ba7291d383b82ce1c2fe324f69a42da2d", "status": "affected", "versionType": "git" }, { "version": "d463a43d69f4af85887671d76182437775fd1631", "lessThan": "55a06b32438c222765138727d0a8164b103e8f0d", "status": "affected", "versionType": "git" }, { "version": "d463a43d69f4af85887671d76182437775fd1631", "lessThan": "eb3e1a1cb1634c76d59c5a9cb1a026fc69d40911", "status": "affected", "versionType": "git" }, { "version": "d463a43d69f4af85887671d76182437775fd1631", "lessThan": "3bf7dba8dba9a05774b846affec61a3624ddba38", "status": "affected", "versionType": "git" }, { "version": "d463a43d69f4af85887671d76182437775fd1631", "lessThan": "58c2d3e954c13694ef6e820a5e9456461bb9e7df", "status": "affected", "versionType": "git" }, { "version": "d463a43d69f4af85887671d76182437775fd1631", "lessThan": "332c444f4dc6fa1e8b8637c9e82d29e97f768656", "status": "affected", "versionType": "git" }, { "version": "d463a43d69f4af85887671d76182437775fd1631", "lessThan": "a3eb169ee297aa99670ba927c659990bd1e453f3", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/ceph/mdsmap.c" ], "versions": [ { "version": "4.7", "status": "affected" }, { "version": "0", "lessThan": "4.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "4.7", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/0c4bcc3ba7291d383b82ce1c2fe324f69a42da2d" }, { "url": "https://git.kernel.org/stable/c/55a06b32438c222765138727d0a8164b103e8f0d" }, { "url": "https://git.kernel.org/stable/c/eb3e1a1cb1634c76d59c5a9cb1a026fc69d40911" }, { "url": "https://git.kernel.org/stable/c/3bf7dba8dba9a05774b846affec61a3624ddba38" }, { "url": "https://git.kernel.org/stable/c/58c2d3e954c13694ef6e820a5e9456461bb9e7df" }, { "url": "https://git.kernel.org/stable/c/332c444f4dc6fa1e8b8637c9e82d29e97f768656" }, { "url": "https://git.kernel.org/stable/c/a3eb169ee297aa99670ba927c659990bd1e453f3" } ], "title": "ceph: bound num_export_targets array for mds info v2/v3", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-89650", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:25:14.842752Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:46.677Z" } } ] } }