ceph: bound xattr value length in __build_xattrs()
In the Linux kernel, the following vulnerability has been resolved: ceph: bound xattr value length in __build_xattrs() __build_xattrs() decodes the MDS-supplied xattr blob one attribute at a time. For each attribute it reads a 32-bit name length, advances past the name bytes, reads a 32-bit value length, records the value pointer, and advances past the value bytes. The two length fields are read with ceph_decode_32_safe(), but the value bytes themselves are advanced over with a bare "p += len" and no ceph_decode_need() check that "len" bytes remain in the blob. For every attribute except the last, the next iteration's ceph_decode_32_safe() on the following name length implicitly verifies that the previous value did not run past the blob end. The final attribute has no successor, so its decoded value length is never checked against the blob bounds. A malicious or compromised metadata server can set the last attribute's value length larger than the bytes actually present in the blob. The blob is a dedicated kvmalloc() allocation sized to the wire length (ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the oversized length in xattr->val_len verbatim, and a later getxattr(2) runs memcpy(value, xattr->val, xattr->val_len) into a user-supplied buffer, copying bytes past the end of the allocation back to user space. Impact: a malicious metadata server discloses adjacent kernel heap bytes to a local user via getxattr(2) on a CephFS file. Add the missing ceph_decode_nee
CVE-2026-89649
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-2026-89649
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": "355da1eb7a1f91c276b991764e951bbcd8047599",
"lessThan": "848b80ca6b410f350d08b8ac19a00ef88223f2ea",
"versionType": "git"
},
{
"status": "affected",
"version": "355da1eb7a1f91c276b991764e951bbcd8047599",
"lessThan": "01e3f19c301d492e12f16b3b463ac14d7cf3ebe7",
"versionType": "git"
},
{
"status": "affected",
"version": "355da1eb7a1f91c276b991764e951bbcd8047599",
"lessThan": "cb0cd79ae80476d1bc06bd9678484b6736f19588",
"versionType": "git"
},
{
"status": "affected",
"version": "355da1eb7a1f91c276b991764e951bbcd8047599",
"lessThan": "61f085cb8976c9cebc90e1a8933e4cc1ad8b0fce",
"versionType": "git"
},
{
"status": "affected",
"version": "355da1eb7a1f91c276b991764e951bbcd8047599",
"lessThan": "38be2f3c41ecaba58bb92dc16603e09ba9fd64f1",
"versionType": "git"
},
{
"status": "affected",
"version": "355da1eb7a1f91c276b991764e951bbcd8047599",
"lessThan": "1dd356310b1660215f9a3626580bf8b363ef981e",
"versionType": "git"
},
{
"status": "affected",
"version": "355da1eb7a1f91c276b991764e951bbcd8047599",
"lessThan": "b12b3320c81fd72ab36388fb2445fec9c3038f10",
"versionType": "git"
},
{
"status": "affected",
"version": "355da1eb7a1f91c276b991764e951bbcd8047599",
"lessThan": "68d541754d6cd3bb98d1fd8314f57e5eb533557d",
"versionType": "git"
}
],
"programFiles": [
"fs/ceph/xattr.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.34"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.34",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"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/xattr.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89649
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #35144 · Revision 1
- Added to Heist Feed
- Publisher date