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Response snapshot Oct 27, 2026, 10:41 UTC

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VulnerabilityCVE-2026-63858

Linux kernel: netfilter: nf_tables: add hook transactions for device deletions

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: add hook transactions for device deletions Restore the flag that indicates that the hook is going away, ie.

At a glance

Exploited
Not known
Severity
7.8 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-2026-63858 (opens a new tab)

What happened

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_tables: add hook transactions for device deletions

Restore the flag that indicates that the hook is going away, ie. NFT_HOOK_REMOVE, but add a new transaction object to track deletion of hooks without altering the basechain/flowtable hook_list during the preparation phase.

The existing approach that moves the hook from the basechain/flowtable hook_list to transaction hook_list breaks netlink dump path readers of this RCU-protected list.

Continue reading

It should be possible use an array for nft_trans_hook to store the deleted hooks to compact the representation but I am not expecting many hook object, specially now that wildcard support for devices is in place.

Note that the nft_trans_chain_hooks() list contains a list of struct nft_trans_hook objects for DELCHAIN and DELFLOWTABLE commands, while this list stores struct nft_hook objects for NEWCHAIN and NEWFLOWTABLE. Note that new commands can be updated to use nft_trans_hook for consistency.

This patch also adapts the event notification path to deal with the list of hook transactions.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 0.8%

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-2026-63858 (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-2026-63858, scored 2026-10-26. 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, October 26). Linux kernel: netfilter: nf_tables: add hook transactions for device deletions (CVE-2026-63858). https://kevwire.com/record/CVE-2026-63858

MLA

"Linux kernel: netfilter: nf_tables: add hook transactions for device deletions (CVE-2026-63858)." KEVWire, 26 Oct. 2026, kevwire.com/record/CVE-2026-63858.

Chicago

KEVWire. "Linux kernel: netfilter: nf_tables: add hook transactions for device deletions (CVE-2026-63858)." Last modified October 26, 2026. https://kevwire.com/record/CVE-2026-63858.

Evidence summary (plain text)

Linux kernel: netfilter: nf_tables: add hook transactions for device deletions (Jul 19, 2026).
In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_tables: add hook transactions for device deletions

Restore the flag that indicates that the hook is going away, ie.
NFT_HOOK_REMOVE, but add a new transaction object to track deletion
of hooks without altering the basechain/flowtable hook_list during
the preparation phase.

The existing approach that moves the hook from the basechain/flowtable
hook_list to transaction hook_list breaks netlink dump path readers
of this RCU-protected list.

It should be possible use an array for nft_trans_hook to store the
deleted hooks to compact the representation but I am not expecting
many hook object, specially now that wildcard support for devices
is in place.

Note that the nft_trans_chain_hooks() list contains a list of struct
nft_trans_hook objects for DELCHAIN and DELFLOWTABLE commands, while
this list stores struct nft_hook objects for NEWCHAIN and NEWFLOWTABLE.
Note that new commands can be updated to use nft_trans_hook for
consistency.

This patch also adapts the event notification path to deal with the list
of hook transactions.
CVSS 7.8 (version 3.1; evidence as of Oct 26, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-63858).
EPSS 0.1% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-63858&date=2026-10-26).
Sources:
NVD CVE-2026-63858: https://nvd.nist.gov/vuln/detail/CVE-2026-63858
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-26T16:21:04.749Z&lastModEndDate=2026-10-26T17:50:56.936Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-26T15:50:57.770Z&lastModEndDate=2026-10-26T17:20:56.094Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-26T15:21:00.016Z&lastModEndDate=2026-10-26T16:50:55.493Z&resultsPerPage=500&startIndex=0
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-63858&date=2026-10-26
Record ID: CVE-2026-63858.
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: Oct 27, 2026, 07:41 UTC. Ingestion is not an independent editorial investigation.

NVD status: Analyzed. 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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Record details

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