CVE-2026-89657Network attack vector

Client crash via unchecked sparse-read extent offsets

Published Sep 11, 2026 · Updated Sep 11, 2026

Denial of service in Linux kernel 6.6 libceph allows remote authenticated users to crash Ceph clients via a malformed OSD reply. osd_sparse_read() trusts each OSD-supplied extent offset after checking only the total data length, allowing a far-forward extent to advance the message-data cursor beyond the request buffer. The path requires an authenticated malicious or compromised OSD peer; ceph_msg_data_next() then reaches a kernel assertion and interrupts the client.

CVSS severityUnavailable
Unscored
EPSS probability0.60%
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 Linux kernel 6.6 libceph allows remote authenticated users to crash Ceph clients via a malformed OSD reply. osd_sparse_read() trusts each OSD-supplied extent offset after checking only the total data length, allowing a far-forward extent to advance the message-data cursor beyond the request buffer. The path requires an authenticated malicious or compromised OSD peer; ceph_msg_data_next() then reaches a kernel assertion and interrupts the client.

The record

CVE
CVE-2026-89657
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 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=6.6
  2. Affected versionversion=f628d799972799023d32c2542bb2639eb8c4f84e <058ffa81f9440c5b4714685611cf697fd3739ec9
  3. Affected versionversion=f628d799972799023d32c2542bb2639eb8c4f84e <201db408872ca12cf09e36bf0f560138c3dcfa1c
  4. Affected versionversion=f628d799972799023d32c2542bb2639eb8c4f84e <2571b35883268a266554e80d368e67fdfea7fb9d
  5. Affected versionversion=f628d799972799023d32c2542bb2639eb8c4f84e <9ec08b7499a62c6d4afa93d36ab47a43fcad57d1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.6; version=f628d799972799023d32c2542bb2639eb8c4f84e <058ffa81f9440c5b4714685611cf697fd3739ec9; version=f628d799972799023d32c2542bb2639eb8c4f84e <201db408872ca12cf09e36bf0f560138c3dcfa1c; version=f628d799972799023d32c2542bb2639eb8c4f84e <2571b35883268a266554e80d368e67fdfea7fb9d; version=f628d799972799023d32c2542bb2639eb8c4f84e <9ec08b7499a62c6d4afa93d36ab47a43fcad57d1

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.

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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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