CVE-2026-64207

Local system crash via GSO backlog miscount

Published Jul 20, 2026 · Updated Jul 20, 2026

Denial of service in the Linux Kernel allows local users to crash the system by sending GSO traffic through DualPI2 under a QFQ parent. When sch_dualpi2.c splits a GSO skb, it reports every segment to the parent before the original skb is counted again, leaving qlen one too high. Exploitation requires local low-privileged access and the specified qdisc hierarchy; after real packets drain, QFQ passes a NULL aggregate to qfq_peek_skb.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux Kernel allows local users to crash the system by sending GSO traffic through DualPI2 under a QFQ parent. When sch_dualpi2.c splits a GSO skb, it reports every segment to the parent before the original skb is counted again, leaving qlen one too high. Exploitation requires local low-privileged access and the specified qdisc hierarchy; after real packets drain, QFQ passes a NULL aggregate to qfq_peek_skb.

The record

CVE
CVE-2026-64207
Published
Jul 20, 2026
Updated
Jul 20, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=6.17
  2. Affected versionversion=8f9516daedd67097a0c6e463fcb7a42b5ee9d477 <05ed733b65ab977dd931e7f7ac0f62fdb81205c2
  3. Affected versionversion=8f9516daedd67097a0c6e463fcb7a42b5ee9d477 <806586e33891066487db1f002be3d455cda6b516
  4. Affected versionversion=8f9516daedd67097a0c6e463fcb7a42b5ee9d477 <c4b70c1512b8f9f33f23c2c8196dfd1210207681

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.17; version=8f9516daedd67097a0c6e463fcb7a42b5ee9d477 <05ed733b65ab977dd931e7f7ac0f62fdb81205c2; version=8f9516daedd67097a0c6e463fcb7a42b5ee9d477 <806586e33891066487db1f002be3d455cda6b516; version=8f9516daedd67097a0c6e463fcb7a42b5ee9d477 <c4b70c1512b8f9f33f23c2c8196dfd1210207681

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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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