CVE-2026-98104Public exploit

Traffic-control filter corruption via duplicate handle allocation

Published Sep 25, 2026 · Updated Sep 25, 2026

Duplicate-handle generation in Linux cls_u32 allows local users to corrupt traffic-control filter state after exhausting an ID pool. gen_new_kid() returns an already-live maximum handle after both ID allocation ranges fill, and u32_change() inserts it without detecting the collision. Reproduction requires CONFIG_NET_SCHED and CONFIG_CLS_U32, a clsact qdisc, 4,096 auto-handle additions, and namespace-local CAP_NET_ADMIN.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Duplicate-handle generation in Linux cls_u32 allows local users to corrupt traffic-control filter state after exhausting an ID pool. gen_new_kid() returns an already-live maximum handle after both ID allocation ranges fill, and u32_change() inserts it without detecting the collision. Reproduction requires CONFIG_NET_SCHED and CONFIG_CLS_U32, a clsact qdisc, 4,096 auto-handle additions, and namespace-local CAP_NET_ADMIN.

The record

CVE
CVE-2026-98104
Published
Sep 25, 2026
Updated
Sep 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1562.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 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=3.16
  2. Affected versionversion=7801db8aec957fa6610efe0ee26a6c8bc0f1d73b <6890e28840bae4f6805e8de981c4ec8e12a4e064
  3. Affected versionversion=7801db8aec957fa6610efe0ee26a6c8bc0f1d73b <d7e7e98d23f42a92d9ab7e36302bd96bd9b33b5f
  4. Affected versionversion=7801db8aec957fa6610efe0ee26a6c8bc0f1d73b <f594f04268d01c5fdc975f3f51fc219ea2159ac6
  5. Affected versionversion=7801db8aec957fa6610efe0ee26a6c8bc0f1d73b <feab9261b537df4ebb8350e4779bc185373059fd

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=3.16; version=7801db8aec957fa6610efe0ee26a6c8bc0f1d73b <6890e28840bae4f6805e8de981c4ec8e12a4e064; version=7801db8aec957fa6610efe0ee26a6c8bc0f1d73b <d7e7e98d23f42a92d9ab7e36302bd96bd9b33b5f; version=7801db8aec957fa6610efe0ee26a6c8bc0f1d73b <f594f04268d01c5fdc975f3f51fc219ea2159ac6; version=7801db8aec957fa6610efe0ee26a6c8bc0f1d73b <feab9261b537df4ebb8350e4779bc185373059fd

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 exploitPublished

Weakness, pattern, technique

T1562.004Disable or Modify System Firewall

Public exploit references

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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