7.5
HIGH
CVSS 3.1
CVE-2026-68155
libceph: Reject monmaps advertising zero monitors
Overview
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 ]
Details
INFO
Published Date :
Aug. 10, 2026, 1:20 p.m.
Last Modified :
Aug. 18, 2026, 7:16 a.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Scoring
CVSS Scores
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for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
Reject monmaps advertising zero monitors to prevent client crashes and invalid states.
- Apply the kernel patch for libceph.
- Ensure monmap num_mon is greater than zero.
- Validate monitor count in monmap decode.
- Update the Linux kernel.
References
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CVE-2026-68155.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-68155 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-68155
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-68155 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-68155 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 18, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '0591a15815b498be628a937146e44487d599ba33', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'cd0d41bc569632eaaeccde9d2a6bc919ec00c407', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e67e8b694872c9bc66996040f9de9242f6236ed9', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '3b249546f59c3d6d3592c10657f82bc3f1faa07c', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '40480eee361ed9676b3f844d532ac28b47251634', 'versionType': 'git'}, {'status': 'affected', 'version': '0', 'lessThan': '6.6.148', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.12.101', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.18.42', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '7.1.6', 'versionType': 'semver'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'ba75bb98cfb93b62c54af25bf67ff90857264bbe', 'lessThan': '0591a15815b498be628a937146e44487d599ba33', 'versionType': 'git'}, {'status': 'affected', 'version': 'ba75bb98cfb93b62c54af25bf67ff90857264bbe', 'lessThan': 'cd0d41bc569632eaaeccde9d2a6bc919ec00c407', 'versionType': 'git'}, {'status': 'affected', 'version': 'ba75bb98cfb93b62c54af25bf67ff90857264bbe', 'lessThan': 'e67e8b694872c9bc66996040f9de9242f6236ed9', 'versionType': 'git'}, {'status': 'affected', 'version': 'ba75bb98cfb93b62c54af25bf67ff90857264bbe', 'lessThan': '3b249546f59c3d6d3592c10657f82bc3f1faa07c', 'versionType': 'git'}, {'status': 'affected', 'version': 'ba75bb98cfb93b62c54af25bf67ff90857264bbe', 'lessThan': '40480eee361ed9676b3f844d532ac28b47251634', 'versionType': 'git'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2.6.34'}, {'status': 'unaffected', 'version': '0', 'lessThan': '2.6.34', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'affected'}] -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '0591a15815b498be628a937146e44487d599ba33', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'cd0d41bc569632eaaeccde9d2a6bc919ec00c407', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e67e8b694872c9bc66996040f9de9242f6236ed9', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '3b249546f59c3d6d3592c10657f82bc3f1faa07c', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '40480eee361ed9676b3f844d532ac28b47251634', 'versionType': 'git'}, {'status': 'affected', 'version': '0', 'lessThan': '6.6.148', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.12.101', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.18.42', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '7.1.6', 'versionType': 'semver'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc5', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '0591a15815b498be628a937146e44487d599ba33', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'cd0d41bc569632eaaeccde9d2a6bc919ec00c407', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e67e8b694872c9bc66996040f9de9242f6236ed9', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '3b249546f59c3d6d3592c10657f82bc3f1faa07c', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '40480eee361ed9676b3f844d532ac28b47251634', 'versionType': 'git'}, {'status': 'affected', 'version': '0', 'lessThan': '6.6.148', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.12.101', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.18.42', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '7.1.6', 'versionType': 'semver'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'affected'}] -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 13, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 10, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '0591a15815b498be628a937146e44487d599ba33', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'cd0d41bc569632eaaeccde9d2a6bc919ec00c407', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'e67e8b694872c9bc66996040f9de9242f6236ed9', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '3b249546f59c3d6d3592c10657f82bc3f1faa07c', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '40480eee361ed9676b3f844d532ac28b47251634', 'versionType': 'git'}, {'status': 'affected', 'version': '0', 'lessThan': '6.6.148', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.12.101', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.18.42', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '7.1.6', 'versionType': 'semver'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc5', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ceph/mon_client.c'], 'defaultStatus': 'affected'}] Added 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 ] Added Reference https://git.kernel.org/stable/c/0591a15815b498be628a937146e44487d599ba33 Added Reference https://git.kernel.org/stable/c/3b249546f59c3d6d3592c10657f82bc3f1faa07c Added Reference https://git.kernel.org/stable/c/40480eee361ed9676b3f844d532ac28b47251634 Added Reference https://git.kernel.org/stable/c/cd0d41bc569632eaaeccde9d2a6bc919ec00c407 Added Reference https://git.kernel.org/stable/c/e67e8b694872c9bc66996040f9de9242f6236ed9
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.