ocfs2: validate rl_used against rl_count in refcount block validator
In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate rl_used against rl_count in refcount block validator ocfs2_find_refcount_rec_in_rl() walks the on-disk refcount record array with: for (; i < le16_to_cpu(rb->rf_records.rl_used); i++) { rec = &rb->rf_records.rl_recs[i]; ... rl_recs[] lives in a single metadata block (4096 bytes on the common configuration), so its real capacity is fixed by ocfs2_refcount_recs_per_rb(sb) (247 records for a 4K block with the 16-byte ocfs2_refcount_rec). rl_used and rl_count are both read directly off disk by ocfs2_validate_refcount_block() and are never checked against that capacity, nor against each other, before any refcount/reflink/CoW operation walks the array. A crafted (or corrupted) refcount block with rl_used == 0xffff makes the loop above walk far past the end of the block, dereferencing rl_recs[i] for i up to 65534. The resulting index is then handed to the sibling ocfs2_insert_refcount_rec(), whose insert-shift does: if (index < le16_to_cpu(rf_list->rl_used)) memmove(&rf_list->rl_recs[index + 1], &rf_list->rl_recs[index], (le16_to_cpu(rf_list->rl_used) - index) * sizeof(struct ocfs2_refcount_rec)); i.e. a memmove() of up to (0xffff - index) * 16 bytes (~1 MiB) from an offset already past the block. This is reachable from an ordinary reflink (FICLONE) against a crafted/corrupted ocfs2 image: attaching an extent whose cpos sorts past every real record in the leaf forces the lookup to run off the end ins
CVE-2026-89493
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-2026-89493
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": "f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4",
"lessThan": "f882e9e32d017a6569b2996c63ba3864717788e6",
"versionType": "git"
},
{
"status": "affected",
"version": "f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4",
"lessThan": "5593b63028cb43a6cda75a65ce1db95f00ea6857",
"versionType": "git"
},
{
"status": "affected",
"version": "f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4",
"lessThan": "c8b02f4ee91e757b3fff556c7168b24b7ae55132",
"versionType": "git"
},
{
"status": "affected",
"version": "f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4",
"lessThan": "97584e93fc49a2d59252ac60467e9279f11b1b5b",
"versionType": "git"
},
{
"status": "affected",
"version": "f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4",
"lessThan": "af56e90cb546cb0c47bef059335365283f61d6a4",
"versionType": "git"
},
{
"status": "affected",
"version": "f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4",
"lessThan": "0761d2c9494424469a0d30a9da3496ca010b0b2d",
"versionType": "git"
},
{
"status": "affected",
"version": "f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4",
"lessThan": "04ead708e13ddcb9c39319cbe02a18cef99cb823",
"versionType": "git"
},
{
"status": "affected",
"version": "f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4",
"lessThan": "4ca62df6bc0708947b48da3f6a712ecb8e73929c",
"versionType": "git"
}
],
"programFiles": [
"fs/ocfs2/refcounttree.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.32"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.32",
"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/ocfs2/refcounttree.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89493
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #35018 · Revision 1
- Added to Heist Feed
- Publisher date