Linux Kernel up to 7.2-rc4 libceph ceph_monmap_decode num_mon input validation

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.7$0-$5k0.54+

Summaryinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc4. Affected by this vulnerability is the function ceph_monmap_decode of the component libceph. Executing a manipulation of the argument num_mon can lead to input validation. This vulnerability appears as CVE-2026-68155. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc4 and classified as problematic. This vulnerability affects the function ceph_monmap_decode of the component libceph. The manipulation of the argument num_mon with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect availability. CVE summarizes:

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 ]

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-68155 since 07/30/2026. The exploitation appears to be easy. The attack can be initiated remotely. Additional levels of successful authentication are necessary for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/10/2026).

Upgrading to version 6.6.148, 6.12.101, 6.18.42, 7.1.6 or 7.2-rc5 eliminates this vulnerability. Applying the patch 0591a15815b498be628a937146e44487d599ba33/cd0d41bc569632eaaeccde9d2a6bc919ec00c407/e67e8b694872c9bc66996040f9de9242f6236ed9/3b249546f59c3d6d3592c10657f82bc3f1faa07c/40480eee361ed9676b3f844d532ac28b47251634 is able to eliminate this problem.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.9
VulDB Meta Temp Score: 4.7

VulDB Base Score: 4.9
VulDB Temp Score: 4.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.148/6.12.101/6.18.42/7.1.6/7.2-rc5
Patch: 0591a15815b498be628a937146e44487d599ba33/cd0d41bc569632eaaeccde9d2a6bc919ec00c407/e67e8b694872c9bc66996040f9de9242f6236ed9/3b249546f59c3d6d3592c10657f82bc3f1faa07c/40480eee361ed9676b3f844d532ac28b47251634

Timelineinfo

07/30/2026 CVE reserved
08/10/2026 +11 days Advisory disclosed
08/10/2026 +0 days VulDB entry created
08/10/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-68155 (🔒)
GCVE (CVE): GCVE-0-2026-68155
GCVE (VulDB): GCVE-100-387508

Entryinfo

Created: 08/10/2026 15:30
Changes: 08/10/2026 15:30 (60)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you know our Splunk app?

Download it now for free!