libceph: Reject monmaps advertising zero monitors

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-68155
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-10 13:20:01 UTC
Updated2026-08-18 07:16:50 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: libceph: Reject monmaps advertising zero monitors A message of type CEPH_MSG_MON_MAP contains a monmap that is sent from a monitor to the client. This monmap contains information about the existing monitors in the cluster. Currently, a monmap indicating that there are zero monitors in the cluster is treated as valid. However, it is impossible to have zero monitors in the cluster and still receive a valid monmap from a monitor. Therefore, such a monmap must be corrupted and should be treated as invalid. Furthermore, a monmap with a monitor count of zero can subsequently crash the client when attempting to open a session with a monitor in __open_session(). This happens because the "BUG_ON(monc->monmap->num_mon < 1)" assertion in pick_new_mon() is triggered. This patch extends a check in ceph_monmap_decode() to also reject arriving mon_maps with num_mon == 0 rather than only with num_mon > CEPH_MAX_MON. [ idryomov: drop "log output for unusual values of num_mon" part ]

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.006030000 probability, percentile 0.459950000 (date 2026-08-17)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected ba75bb98cfb93b62c54af25bf67ff90857264bbe 0591a15815b498be628a937146e44487d599ba33 git Not specified
CNA Linux Linux affected ba75bb98cfb93b62c54af25bf67ff90857264bbe cd0d41bc569632eaaeccde9d2a6bc919ec00c407 git Not specified
CNA Linux Linux affected ba75bb98cfb93b62c54af25bf67ff90857264bbe e67e8b694872c9bc66996040f9de9242f6236ed9 git Not specified
CNA Linux Linux affected ba75bb98cfb93b62c54af25bf67ff90857264bbe 3b249546f59c3d6d3592c10657f82bc3f1faa07c git Not specified
CNA Linux Linux affected ba75bb98cfb93b62c54af25bf67ff90857264bbe 40480eee361ed9676b3f844d532ac28b47251634 git Not specified
CNA Linux Linux affected 2.6.34 Not specified
CNA Linux Linux unaffected 2.6.34 semver Not specified
CNA Linux Linux unaffected 6.6.148 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.101 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.42 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.6 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/40480eee361ed9676b3f844d532ac28b47251634 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/cd0d41bc569632eaaeccde9d2a6bc919ec00c407 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0591a15815b498be628a937146e44487d599ba33 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e67e8b694872c9bc66996040f9de9242f6236ed9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3b249546f59c3d6d3592c10657f82bc3f1faa07c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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