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Response snapshot Nov 6, 2026, 19:41 UTC

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VulnerabilityCVE-2026-46130

Linux kernel: 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.

At a glance

Exploited
Not known
Severity
7.1 High (CVSS 3.1)
Chance of exploitation
0.1% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-46130 (opens a new tab)

What happened

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.

Continue reading

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.

Scores and how they were measured

CVSS base severity

7.1

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.1%

Scored Percentile 2.3%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-46130 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  5. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-46130, scored 2026-11-06. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 6). Linux kernel: dm-verity-fec: fix reading parity bytes split across blocks (take 3) (CVE-2026-46130). https://kevwire.com/record/CVE-2026-46130

MLA

"Linux kernel: dm-verity-fec: fix reading parity bytes split across blocks (take 3) (CVE-2026-46130)." KEVWire, 6 Nov. 2026, kevwire.com/record/CVE-2026-46130.

Chicago

KEVWire. "Linux kernel: dm-verity-fec: fix reading parity bytes split across blocks (take 3) (CVE-2026-46130)." Last modified November 6, 2026. https://kevwire.com/record/CVE-2026-46130.

Evidence summary (plain text)

Linux kernel: dm-verity-fec: fix reading parity bytes split across blocks (take 3) (May 28, 2026).
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.
CVSS 7.1 (version 3.1; evidence as of Nov 6, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-46130).
EPSS 0.1% for the following 30 days, scored Nov 6, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-46130&date=2026-11-06).
Sources:
NVD CVE-2026-46130: https://nvd.nist.gov/vuln/detail/CVE-2026-46130
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-06T17:06:05.906Z&lastModEndDate=2026-11-06T18:35:59.598Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-06T16:31:13.932Z&lastModEndDate=2026-11-06T18:05:57.615Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-06T15:50:58.372Z&lastModEndDate=2026-11-06T17:30:57.197Z&resultsPerPage=500&startIndex=0
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-46130&date=2026-11-06
Record ID: CVE-2026-46130.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 6, 2026, 19:36 UTC. Ingestion is not an independent editorial investigation.

NVD status: Undergoing Analysis. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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