CVE-2026-89650Network attack vector

Kernel out-of-bounds read via oversized target count

Published Sep 11, 2026 · Updated Sep 11, 2026

Out-of-bounds read in the Linux kernel CephFS client allows remote attackers to trigger a read past a message buffer via a crafted MDS map. ceph_mdsmap_decode() advances its cursor by an unchecked num_export_targets-sized array for version 2 or 3 records before ceph_decode_32() reads entries. Exploitation requires a malicious or compromised monitor, or an on-path position on an unsigned and unencrypted session; read values remain internal rather than being disclosed.

CVSS severityUnavailable
Unscored
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux kernel CephFS client allows remote attackers to trigger a read past a message buffer via a crafted MDS map. ceph_mdsmap_decode() advances its cursor by an unchecked num_export_targets-sized array for version 2 or 3 records before ceph_decode_32() reads entries. Exploitation requires a malicious or compromised monitor, or an on-path position on an unsigned and unencrypted session; read values remain internal rather than being disclosed.

The record

CVE
CVE-2026-89650
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

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

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=4.7
  2. Affected versionversion=d463a43d69f4af85887671d76182437775fd1631 <332c444f4dc6fa1e8b8637c9e82d29e97f768656
  3. Affected versionversion=d463a43d69f4af85887671d76182437775fd1631 <3bf7dba8dba9a05774b846affec61a3624ddba38
  4. Affected versionversion=d463a43d69f4af85887671d76182437775fd1631 <58c2d3e954c13694ef6e820a5e9456461bb9e7df
  5. Affected versionversion=d463a43d69f4af85887671d76182437775fd1631 <a3eb169ee297aa99670ba927c659990bd1e453f3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.7; version=d463a43d69f4af85887671d76182437775fd1631 <332c444f4dc6fa1e8b8637c9e82d29e97f768656; version=d463a43d69f4af85887671d76182437775fd1631 <3bf7dba8dba9a05774b846affec61a3624ddba38; version=d463a43d69f4af85887671d76182437775fd1631 <58c2d3e954c13694ef6e820a5e9456461bb9e7df; version=d463a43d69f4af85887671d76182437775fd1631 <a3eb169ee297aa99670ba927c659990bd1e453f3

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
Privilegesunauthenticated
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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