libceph: Reject monmaps advertising zero monitors
Priority MEDIUM 40CWE-20Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 16 fixed, 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
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 ]
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00696 53rd percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.271, 5.15.216, 6.1.183 +5Red Hat: 5 advisoriesRed Hat: 16 fixed, 2 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.34 and later | 5.10.271, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.34 and later Fixed in 5.10.271, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2
Red Hat 5 advisories
- RHSA-2026:94996 Released 2026-11-04 · Red Hat rating Criticalkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS AUS (v.8.6) bpftool-4.18.0-372.227.1.el8_6, kernel-4.18.0-372.227.1.el8_6, kernel-abi-stablelists-4.18.0-372.227.1.el8_6 +14
- Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) bpftool-4.18.0-372.227.1.el8_6, kernel-4.18.0-372.227.1.el8_6, kernel-abi-stablelists-4.18.0-372.227.1.el8_6 +14
- RHSA-2026:72468 Released 2026-09-28 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.169.1.el8_10, kernel-4.18.0-553.169.1.el8_10, kernel-abi-stablelists-4.18.0-553.169.1.el8_10 +19
- Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.169.1.el8_10
- RHSA-2026:72467 Released 2026-09-28 · Red Hat rating Importantkernel-rt security update
- Red Hat Enterprise Linux NFV (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-debug-4.18.0-553.169.1.rt7.510.el8_10 +9
- 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-debug-4.18.0-553.169.1.rt7.510.el8_10 +7
Show 2 more Red Hat advisories
- RHSA-2026:70459 Released 2026-09-23 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.50.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.50.1.el9_8, kernel-64k-devel-5.14.0-687.50.1.el9_8 +12
- 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-64k-core-5.14.0-687.50.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.50.1.el9_8, libperf-5.14.0-687.50.1.el9_8
- 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-64k-core-5.14.0-687.50.1.el9_8 +21
- 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-debug-5.14.0-687.50.1.el9_8 +9
- RHSA-2026:70498 Released 2026-09-23 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.58.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.58.1.el10_2, kernel-64k-devel-6.12.0-211.58.1.el10_2 +12
- 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-64k-core-6.12.0-211.58.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.58.1.el10_2, libperf-6.12.0-211.58.1.el10_2
- 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-64k-core-6.12.0-211.58.1.el10_2 +21
- 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-debug-6.12.0-211.58.1.el10_2 +9
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:70498 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:70459 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:70498 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:72468 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:70459 |
| Red Hat Enterprise Linux BaseOS AUS (v.8.6) | Fixed | RHSA-2026:94996 |
| Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) | Fixed | RHSA-2026:94996 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:72468 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:70498 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:70459 |
| Red Hat Enterprise Linux NFV (v. 8) | Fixed | RHSA-2026:72467 |
| Red Hat Enterprise Linux RT (v. 8) | Fixed | RHSA-2026:72467 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:70498 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:70459 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:70498 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:70459 |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux for NVIDIA 26
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-68155
- 2026-10-03 Alias added: GHSA-2v58-jx7r-h3cm
- 2026-10-03 Fix available: Linux/[email protected], Linux/Linux@ba5f0015bfd376d764163045a61c17be75f44dae · CNA
- 2026-10-03 1 new reference · CNA
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-16 Priority changed: LOW → MEDIUM
- 2026-10-20 Weakness changed · CISA ADP
- 2026-10-30 Affected versions changed · Red Hat
- 2026-11-04 Fix available: RHSA-2026:94996 · Red Hat
- 2026-11-04 Fix available: Red Hat Enterprise Linux BaseOS AUS (v.8.6), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/ba5f0015bfd376d764163045a61c17be75f44dae
- https://git.kernel.org/stable/c/caf082ef8609a6ac26159ce115f55ab7d00231a3
- https://git.kernel.org/stable/c/e3ccd4ecab09b22f507f49cb7ed9990c7158ceab
- https://git.kernel.org/stable/c/0591a15815b498be628a937146e44487d599ba33
- https://git.kernel.org/stable/c/cd0d41bc569632eaaeccde9d2a6bc919ec00c407
- https://git.kernel.org/stable/c/e67e8b694872c9bc66996040f9de9242f6236ed9
- https://git.kernel.org/stable/c/3b249546f59c3d6d3592c10657f82bc3f1faa07c
- https://git.kernel.org/stable/c/40480eee361ed9676b3f844d532ac28b47251634
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Sources
- CVE-2026-68155 · CVE Program
- CVE-2026-68155 · NVD
- FIRST EPSS
- GHSA-2v58-jx7r-h3cm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-68155 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences