dm-verity-fec: fix reading parity bytes split across blocks (take 3)
In the Linux kernel, the following vulnerability has been resolved: dm-verity-fec: fix reading parity bytes split across blocks (take 3) fec_decode_bufs() assumes that the parity bytes of the first RS codeword it decodes are never split across parity blocks. This assumption is false. Consider v->fec->block_size == 4096 && v->fec->roots == 17 && fio->nbufs == 1, for example. In that case, each call to fec_decode_bufs() consumes v->fec->roots * (fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS) = 272 parity bytes. Considering that the parity data for each message block starts on a block boundary, the byte alignment in the parity data will iterate through 272*i mod 4096 until the 3 parity blocks have been consumed. On the 16th call (i=15), the alignment will be 4080 bytes into the first block. Only 16 bytes remain in that block, but 17 parity bytes will be needed. The code reads out-of-bounds from the parity block buffer. Fortunately this doesn't normally happen, since it can occur only for certain non-default values of fec_roots *and* when the maximum number of buffers couldn't be allocated due to low memory. For example with block_size=4096 only the following cases are affected: fec_roots=17: nbufs in [1, 3, 5, 15] fec_roots=19: nbufs in [1, 229] fec_roots=21: nbufs in [1, 3, 5, 13, 15, 39, 65, 195] fec_roots=23: nbufs in [1, 89] Regardless, fix it by refactoring how the parity blocks are read.
CVE-2026-46130
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-2026-46130
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": "12caa73a28f0ae147ec0356b45091edf2462462b",
"lessThan": "03348b440f69417dc3a3c71d8271cff6b05f67fb",
"versionType": "git"
},
{
"status": "affected",
"version": "fc8943886629e26de34867db302c74d465510826",
"lessThan": "dac69d1b76049d7e5f565089a6a7f4502a85b9de",
"versionType": "git"
},
{
"status": "affected",
"version": "6df90c02bae468a3a6110bafbc659884d0c4966c",
"lessThan": "d47281b9a4472cfd73122393e79fbe76b651e46a",
"versionType": "git"
},
{
"status": "affected",
"version": "6df90c02bae468a3a6110bafbc659884d0c4966c",
"lessThan": "3d1b4e2d8ac0a1a1390a117f61ce0ca1c47e3bcb",
"versionType": "git"
},
{
"status": "affected",
"version": "6df90c02bae468a3a6110bafbc659884d0c4966c",
"lessThan": "430a05cb926f6bdf53e81460a2c3a553257f3f61",
"versionType": "git"
},
{
"status": "affected",
"version": "6bc6ee31113b05db605694491bdeb2b1730142f1",
"versionType": "git"
},
{
"status": "affected",
"version": "6.6.72",
"lessThan": "6.6.160",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.12.10",
"lessThan": "6.12.114",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.125",
"lessThan": "6.2",
"versionType": "semver"
}
],
"programFiles": [
"drivers/md/dm-verity-fec.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.13"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.13",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.0.7",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/md/dm-verity-fec.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-46130
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #46327 · Revision 1
- Added to Heist Feed
- Publisher date