Vulnerability in Linux

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (42.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-89653: held from 0.007 to 0.005.

EPSS over last 30 days · oldest: 0.007 · newest: 0.005 · change: -0.002

Affected products

References

Frequently asked questions

What is CVE-2026-89653?
CVE-2026-89653 is a critical-severity vulnerability in Linux. CVSS score: 9.8/10. Published 2026-09-11.
How severe is CVE-2026-89653?
Critical severity. CVSS v3 base score is 9.8 out of 10.