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ceph: bound num_export_targets array for mds info v2/v3

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ceph: bound num_export_targets array for mds info v2/v3 ceph_mdsmap_decode() in fs/ceph/mdsmap.c reads num_export_targets from each per-mds info record and advances the decode cursor by num_export_targets * sizeof(u32) without first checking that many bytes remain. The only upper-bound check that catches a runaway cursor (*p > info_end) is gated on info_v >= 4, because info_end is left NULL for info_v 2 and 3. When the monitor sends an MDS map whose per-mds info version is 2 or 3 with an oversized num_export_targets, the cursor moves past the message front buffer and the later export-targets loop calls the unchecked ceph_decode_32() on out-of-bounds memory. A kernel client processes CEPH_MSG_MDS_MAP from its monitor session (net/ceph/mon_client.c dispatches it; fs/ceph/super.c routes it to ceph_mdsc_handle_mdsmap(), which sets end to the front buffer bound and calls ceph_mdsmap_decode()). A malicious or compromised monitor, or an on-path attacker on an unsigned/unencrypted messenger session, can therefore drive an out-of-bounds read in the client kernel; on x86_64 with KASAN it is reported as a slab-out-of-bounds read in ceph_mdsmap_decode(). The decoded values land in the internal info->export_targets[] array, so the consequence is a kernel out-of-bounds read, not an information leak to the attacker. Impact: a malicious or compromised Ceph monitor sending an MDS map with a per-mds info version of 2 or 3 and

Announced Source revision 1
Original source ↗

CVE-2026-89650

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-89650

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "d463a43d69f4af85887671d76182437775fd1631",
        "lessThan": "0c4bcc3ba7291d383b82ce1c2fe324f69a42da2d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d463a43d69f4af85887671d76182437775fd1631",
        "lessThan": "55a06b32438c222765138727d0a8164b103e8f0d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d463a43d69f4af85887671d76182437775fd1631",
        "lessThan": "eb3e1a1cb1634c76d59c5a9cb1a026fc69d40911",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d463a43d69f4af85887671d76182437775fd1631",
        "lessThan": "3bf7dba8dba9a05774b846affec61a3624ddba38",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d463a43d69f4af85887671d76182437775fd1631",
        "lessThan": "58c2d3e954c13694ef6e820a5e9456461bb9e7df",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d463a43d69f4af85887671d76182437775fd1631",
        "lessThan": "332c444f4dc6fa1e8b8637c9e82d29e97f768656",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d463a43d69f4af85887671d76182437775fd1631",
        "lessThan": "a3eb169ee297aa99670ba927c659990bd1e453f3",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/ceph/mdsmap.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.7"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.7",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.109",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.50",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.4",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/ceph/mdsmap.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-89650

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#35143 · Revision 1
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Publisher date
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