ceph: bound num_export_targets array for mds info v2/v3
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
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
- Added to Heist Feed
- Publisher date