Skip to content
Fencer Vulns
high 7.5

CVE-2026-68155 json

libceph: Reject monmaps advertising zero monitors

published 2026-08-10 2 mo ago modified 2026-10-19 20 d ago also EUVD-2026-55541

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

In 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 ]

Patch / fix

  • Linux Linux 5.10.271, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2
  • linux Debian 12 6.1.187-1
  • linux Debian 13 6.12.101-1
  • linux Debian 14 7.1.6-1
  • linux-6.12 Debian 12 6.12.101-1~deb12u1

debian advisories DEBIAN-CVE-2026-68155

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 24.04 LTS 6.8.0-147.147
  • linux Ubuntu 26.04 LTS 7.0.0-38.38
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1067.70
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1071.79

ubuntu advisories UBUNTU-CVE-2026-68155

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt RHEL 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-kvm RHEL 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-core RHEL 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-modules RHEL 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-debug-kvm RHEL 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-debug-core RHEL 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-debug-modules RHEL 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-modules-extra RHEL 8 4.18.0-553.169.1.rt7.510.el8_10

red hat advisories RHSA-2026:72467RHSA-2026:72468RHSA-2026:70498RHSA-2026:70459

  • kernel-64kb SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS, SLE High Performance Computing 15 SP5-ESPOS 5.14.21-150500.55.192.2
  • kernel-syms SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.192.1
  • kernel-source SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.192.2
  • kernel-default SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +3 more 5.14.21-150500.55.192.2
  • kernel-obs-build SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.192.2
  • kernel-default-base SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.192.2.150500.6.89.2
  • kernel-rt SLE Micro 5.5 5.14.21-150500.13.164.1
  • kernel-source-rt SLE Micro 5.5 5.14.21-150500.13.164.1

suse advisories SUSE-SU-2026:4667-1SUSE-SU-2026:4665-1SUSE-SU-2026:4254-1SUSE-SU-2026:4369-1SUSE-SU-2026:4284-1SUSE-SU-2026:23887-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1

  • kernel-rt AlmaLinux 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-core AlmaLinux 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-modules AlmaLinux 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-debug-core AlmaLinux 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel-rt-debug-modules-extra AlmaLinux 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel AlmaLinux 8 4.18.0-553.169.1.el8_10

almalinux advisories ALSA-2026:72467ALSA-2026:72468ALSA-2026:70498ALSA-2026:70459

  • kernel-rt Rocky Linux 8 4.18.0-553.169.1.rt7.510.el8_10
  • kernel Rocky Linux 8 4.18.0-553.169.1.el8_10
  • kernel Rocky Linux 9 5.14.0-687.50.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.58.1.el10_2

rocky linux advisories RLSA-2026:72467RLSA-2026:72468RLSA-2026:70459RLSA-2026:70498

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-68155 updated cvss 7.1

kernel: Linux kernel (libceph): Denial of Service due to malformed monitor maps

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.50.1.el9_8, perf 5.14.0-687.50.1.el9_8, rtla 5.14.0-687.50.1.el9_8, python3-perf 5.14.0-687.50.1.el9_8, kernel-devel-matched 5.14.0-687.50.1.el9_8, kernel-64k-devel-matched 5.14.0-687.50.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.58.1.el10_2, perf 6.12.0-211.58.1.el10_2, rtla 6.12.0-211.58.1.el10_2, python3-perf 6.12.0-211.58.1.el10_2, kernel-devel-matched 6.12.0-211.58.1.el10_2, kernel-64k-devel-matched 6.12.0-211.58.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.169.1.el8_10, kernel 4.18.0-553.169.1.el8_10, bpftool 4.18.0-553.169.1.el8_10, kernel-core 4.18.0-553.169.1.el8_10, kernel-tools 4.18.0-553.169.1.el8_10, python3-perf 4.18.0-553.169.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:72468
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.50.1.el9_8, kernel-64k 5.14.0-687.50.1.el9_8, kernel-core 5.14.0-687.50.1.el9_8, kernel-tools 5.14.0-687.50.1.el9_8, kernel-modules 5.14.0-687.50.1.el9_8, kernel-64k-core 5.14.0-687.50.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.58.1.el10_2, kernel-64k 6.12.0-211.58.1.el10_2, kernel-core 6.12.0-211.58.1.el10_2, kernel-tools 6.12.0-211.58.1.el10_2, kernel-modules 6.12.0-211.58.1.el10_2, kernel-64k-core 6.12.0-211.58.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) perf 4.18.0-372.227.1.el8_6, kernel 4.18.0-372.227.1.el8_6, bpftool 4.18.0-372.227.1.el8_6, kernel-core 4.18.0-372.227.1.el8_6, kernel-tools 4.18.0-372.227.1.el8_6, python3-perf 4.18.0-372.227.1.el8_6, +8 more Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) perf 4.18.0-372.227.1.el8_6, kernel 4.18.0-372.227.1.el8_6, bpftool 4.18.0-372.227.1.el8_6, kernel-core 4.18.0-372.227.1.el8_6, kernel-tools 4.18.0-372.227.1.el8_6, python3-perf 4.18.0-372.227.1.el8_6, +8 more
    fixed: vendor fix RHSA-2026:94996
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.50.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.50.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.50.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.50.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.50.1.el9_8
    fixed: vendor fix RHSA-2026:70459
show 9 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.58.1.el10_2
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.169.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.169.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.169.1.el8_10
    fixed: vendor fix RHSA-2026:72468
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-kvm 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-core 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-modules 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-debug-kvm 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-debug-core 4.18.0-553.169.1.rt7.510.el8_10, +4 more
    fixed: vendor fix RHSA-2026:72467
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.50.1.el9_8, kernel-rt-64k 5.14.0-687.50.1.el9_8, kernel-rt-core 5.14.0-687.50.1.el9_8, kernel-rt-modules 5.14.0-687.50.1.el9_8, kernel-rt-64k-core 5.14.0-687.50.1.el9_8, kernel-rt-debug-core 5.14.0-687.50.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.58.1.el10_2, kernel-rt-64k 6.12.0-211.58.1.el10_2, kernel-rt-core 6.12.0-211.58.1.el10_2, kernel-rt-modules 6.12.0-211.58.1.el10_2, kernel-rt-64k-core 6.12.0-211.58.1.el10_2, kernel-rt-debug-core 6.12.0-211.58.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.50.1.el9_8, kernel-rt-core 5.14.0-687.50.1.el9_8, kernel-rt-modules 5.14.0-687.50.1.el9_8, kernel-rt-debug-core 5.14.0-687.50.1.el9_8, kernel-rt-modules-core 5.14.0-687.50.1.el9_8, kernel-rt-debug-modules 5.14.0-687.50.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:70459
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.58.1.el10_2, kernel-rt-core 6.12.0-211.58.1.el10_2, kernel-rt-modules 6.12.0-211.58.1.el10_2, kernel-rt-debug-core 6.12.0-211.58.1.el10_2, kernel-rt-modules-core 6.12.0-211.58.1.el10_2, kernel-rt-debug-modules 6.12.0-211.58.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-core 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-modules 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-debug-core 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-debug-modules 4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-modules-extra 4.18.0-553.169.1.rt7.510.el8_10, +2 more
    fixed: vendor fix RHSA-2026:72467
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux for NVIDIA 26 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
23 d ago

Exploit prediction

0.70% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-20 Improper Input Validation
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.