CVE-2026-98851Hinoki check available

Flowtable deletion blocked via leaked initialization reference

Published Oct 18, 2026 · Updated Oct 18, 2026

Reference leakage in Linux netfilter allows local users to block flowtable deletion through failed flow-offload rule additions. In nft_flow_offload_init(), a failed nf_ct_netns_get() leaves the flowtable use count incremented, and expression cleanup skips the failed expression's destroy callback. Reaching the flaw requires permission to add nftables rules and that initialization failure; the documented consequence is persistent EBUSY on flowtable deletion, not a kernel crash.

CVSS severityUnavailable
Unscored
EPSS probability0.16%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Reference leakage in Linux netfilter allows local users to block flowtable deletion through failed flow-offload rule additions. In nft_flow_offload_init(), a failed nf_ct_netns_get() leaves the flowtable use count incremented, and expression cleanup skips the failed expression's destroy callback. Reaching the flaw requires permission to add nftables rules and that initialization failure; the documented consequence is persistent EBUSY on flowtable deletion, not a kernel crash.

The record

CVE
CVE-2026-98851
Published
Oct 18, 2026
Updated
Oct 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.16
  2. Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <4cd378423a33194a773c267fc58606d28fce95cf
  3. Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <64ac0cb574c740bf723affb79b646eeba920db6b
  4. Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <747928b5d4ff8c8de55138a54c13980e4bb88578
  5. Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <c5f91098edee98c015f78488460a0609e62582a5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=4.16; version=a3c90f7a2323b331ae816d5b0633e68148e25d04 <4cd378423a33194a773c267fc58606d28fce95cf; version=a3c90f7a2323b331ae816d5b0633e68148e25d04 <64ac0cb574c740bf723affb79b646eeba920db6b; version=a3c90f7a2323b331ae816d5b0633e68148e25d04 <747928b5d4ff8c8de55138a54c13980e4bb88578; version=a3c90f7a2323b331ae816d5b0633e68148e25d04 <c5f91098edee98c015f78488460a0609e62582a5

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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