CVE-2026-68156
Description
A flaw was found in the libceph component of the Linux kernel. During an authorizer update, if the authorizer is rebuilt, a stale pointer to a freed memory region can be retained. A remote attacker could exploit this by triggering a specific network reconnection, leading to a use-after-free vulnerability. This memory corruption could result in a system crash or denial of service.
Statement
This use-after-free flaw in the Linux kernel's libceph module can be triggered during Ceph client reconnection. An attacker could exploit this by manipulating Ceph authentication, potentially leading to a system crash or privilege escalation. The impact is significant due to the kernel context, but requires specific Ceph client usage.
Mitigation
To mitigate this vulnerability, prevent the `ceph` kernel module from loading if Ceph client functionality is not in use. Create a file `/etc/modprobe.d/ceph.conf` with `install ceph /bin/true`. If the module is currently loaded, unload it using `rmmod ceph`. A system reboot is required for the changes to take full effect and ensure the module is not reloaded. Unloading the `ceph` module will impact systems actively using Ceph client features.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7 | N/A | 9.8 |
| Attack Vector | Local | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | Low | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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