CVE-2026-68155

HIGHCVSS 7.5/10EPSS 0.60%

Last modified

CVE-2026-68155 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.60% chance of exploitation in the next 30 days.

Description

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 ]

Metrics

EPSS Probability
0.60%

46.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= ba75bb98cfb93b62c54af25bf67ff90857264bbe, < caf082ef8609a6ac26159ce115f55ab7d00231a3; >= ba75bb98cfb93b62c54af25bf67ff90857264bbe, < e3ccd4ecab09b22f507f49cb7ed9990c7158ceab; >= ba75bb98cfb93b62c54af25bf67ff90857264bbe, < 0591a15815b498be628a937146e44487d599ba33; >= ba75bb98cfb93b62c54af25bf67ff90857264bbe, < cd0d41bc569632eaaeccde9d2a6bc919ec00c407; >= ba75bb98cfb93b62c54af25bf67ff90857264bbe, < e67e8b694872c9bc66996040f9de9242f6236ed9; >= ba75bb98cfb93b62c54af25bf67ff90857264bbe, < 3b249546f59c3d6d3592c10657f82bc3f1faa07c; >= ba75bb98cfb93b62c54af25bf67ff90857264bbe, < 40480eee361ed9676b3f844d532ac28b47251634
LinuxLinux2.6.34

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-68155?
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 ]
How severe is CVE-2026-68155?
CVE-2026-68155 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.60% probability of exploitation in the next 30 days.
How do I fix CVE-2026-68155?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST