CVE-2026-98821Public exploit

Kernel crash via integrity metadata type confusion

Published Oct 18, 2026 · Updated Oct 18, 2026

Type confusion in Linux block I/O allows local users to crash the kernel via polled direct I/O with integrity metadata. In block/fops.c, iocb_bio_iopoll() passes iocb->private to bio_poll() as a bio even though metadata I/O leaves it pointing to a uio_meta. Triggering requires io_uring IOPOLL, a protection-information attribute, and access to an integrity-capable block device; the documented consequence is a kernel oops.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in Linux block I/O allows local users to crash the kernel via polled direct I/O with integrity metadata. In block/fops.c, iocb_bio_iopoll() passes iocb->private to bio_poll() as a bio even though metadata I/O leaves it pointing to a uio_meta. Triggering requires io_uring IOPOLL, a protection-information attribute, and access to an integrity-capable block device; the documented consequence is a kernel oops.

The record

CVE
CVE-2026-98821
Published
Oct 18, 2026
Updated
Oct 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
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=17ecefc9fdd8c554e0d03e5a990daef19f930add
  2. Affected versionversion=2729a60bbfb9215997f25372ebe9b7964f038296 <2a42e6fe1293f2e2d579c9fe5bbab056dd8b880e
  3. Affected versionversion=2729a60bbfb9215997f25372ebe9b7964f038296 <c97ef13ad96be0e08af38dfa2ed40cded0b53e1b
  4. Affected versionversion=2729a60bbfb9215997f25372ebe9b7964f038296 <dd33c03cefccdfcb223e9e6262643d64f8c1ae20
  5. Affected versionversion=6.16.8 <6.17
  6. Affected versionversion=6.17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=17ecefc9fdd8c554e0d03e5a990daef19f930add; version=2729a60bbfb9215997f25372ebe9b7964f038296 <2a42e6fe1293f2e2d579c9fe5bbab056dd8b880e; version=2729a60bbfb9215997f25372ebe9b7964f038296 <c97ef13ad96be0e08af38dfa2ed40cded0b53e1b; version=2729a60bbfb9215997f25372ebe9b7964f038296 <dd33c03cefccdfcb223e9e6262643d64f8c1ae20; version=6.16.8 <6.17; version=6.17

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

T1499.004Application or System Exploitation

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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