CVE-2022-50300
Description
A flaw was found in the Linux kernel's btrfs filesystem component. A local user could exploit this use-after-free vulnerability by mounting a btrfs filesystem where a chunk is stored on a missing device without the 'degraded mount' option. This can lead to a system crash, resulting in a Denial of Service (DoS).
Statement
A moderate severity use-after-free flaw was found in the Linux kernel's btrfs filesystem implementation, in the read_one_chunk function, where the error path could access an extent_map after it had been freed. This situation can occur when a chunk is stored on a missing device and the btrfs filesystem is mounted without the 'degraded' mount option. A local user able to mount such a btrfs filesystem could use this flaw to cause a system crash, resulting in a denial of service. Red Hat rated this flaw Moderate (CVSS 6.4) rather than the NIST and CVE.org Important rating (7.8) because exploitation requires local access with high privileges and high attack complexity: an attacker must be able to mount a btrfs filesystem that has a chunk stored on a missing device under specific conditions. No Red Hat products are affected; all in-scope Red Hat Enterprise Linux and Red Hat In-Vehicle OS kernel and kernel-rt components are marked not affected because the vulnerable code is not present in those kernels.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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 | 6.4 | 7.8 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | High | Low | Low |
| Privileges Required | High | Low | None |
| User Interaction | None | None | Required |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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