CVE intelligence

CVE-2026-89653

Vulnerability intelligence

Published Sep 11, 2026Sources checked Oct 30, 2026

9.8CRITICALCVSS out of 10

What this means

Review the available evidence

CVE-2026-89653 and is rated Critical severity with a CVSS score of 9.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 2, 2026

Release Notes

Vendor-listed releases

6.6.157.1-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-89653?

In the Linux kernel, the following vulnerability has been resolved:

ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode

MDSMap export_targets entries are monitor controlled. check_new_map() uses each entry as a bit number in a fixed stack bitmap, so a rank outside the protocol namespace can make set_bit() write past the end of the array.

Reject ranks outside CEPH_MAX_MDS while decoding the map. Do not validate against possible_max_rank here because maps may legitimately reference ranks beyond a temporarily reduced max_mds.

Source: NVD