CVE-2026-89653

ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode

State: Published
Severity: 9.8 Critical
Published: Sep 11, 2026
Updated: Oct 19, 2026
Reserved: Sep 11, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 3740c88ca9cb2210a8dbdd55ea4cec119fbe86feAffected d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 8c823bbab3c24e657469a84db96902ba82d4e8bbAffected d517b3983dd3106ca92d6c5d0d09415a4a09481c to before c4addccd05bacbef2144b4db14853d0308a218acAffected d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 736adee11af36e407ed902264f8b2fb5cf94b62fAffected d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 4d298880f82c42383b36946bafde7ccf4d804c9bAffected d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 96c3f5fbb0d5386e7111426f047f98cec4586674Affected d517b3983dd3106ca92d6c5d0d09415a4a09481c to before aedc9053d909508a5f56c3f49f885fc030df4730Affected
LinuxLinux	5.15Affected before 5.15Not affected 5.15.221 through 5.15.Not affected 6.1.188 through 6.1.Not affected 6.6.157 through 6.6.Not affected 6.12.109 through 6.12.Not affected 6.18.50 through 6.18.Not affected 7.2.4 through 7.2.Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 3740c88ca9cb2210a8dbdd55ea4cec119fbe86feAffected
d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 8c823bbab3c24e657469a84db96902ba82d4e8bbAffected
d517b3983dd3106ca92d6c5d0d09415a4a09481c to before c4addccd05bacbef2144b4db14853d0308a218acAffected
d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 736adee11af36e407ed902264f8b2fb5cf94b62fAffected
d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 4d298880f82c42383b36946bafde7ccf4d804c9bAffected
d517b3983dd3106ca92d6c5d0d09415a4a09481c to before 96c3f5fbb0d5386e7111426f047f98cec4586674Affected
d517b3983dd3106ca92d6c5d0d09415a4a09481c to before aedc9053d909508a5f56c3f49f885fc030df4730Affected

LinuxLinux

5.15Affected
before 5.15Not affected
5.15.221 through 5.15.*Not affected
6.1.188 through 6.1.*Not affected
6.6.157 through 6.6.*Not affected
6.12.109 through 6.12.*Not affected
6.18.50 through 6.18.*Not affected
7.2.4 through 7.2.*Not affected
7.3 and laterNot affected

References

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