CVE-2021-0920
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Last Modified:
Description
A vulnerability was found in unix_dgram_recvmsg in net/unix/af_unix.c in the Linux kernel's garbage collection for Unix domain socket file handlers. In this flaw, a missing cleanup may lead to a use-after-free due to a race problem. This flaw allows a local user to crash the system or escalate their privileges on the system.
A read-after-free memory flaw was found in the Linux kernel's garbage collection for Unix domain socket file handlers in the way users call close() and fget() simultaneously and can potentially trigger a race condition. This flaw allows a local user to crash the system or escalate their privileges on the system.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Additional information
- Bugzilla 2031930: kernel: Use After Free in unix_gc() which could result in a local privilege escalation
- CWE-416: Use After Free
- FAQ: Frequently asked questions about CVE-2021-0920
Common Vulnerability Scoring System (CVSS) Score Details
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).
| Red Hat | NVD | |
|---|---|---|
CVSS v3 Base Score | 7.4 | 6.4 |
Attack Vector | Local | Local |
Attack Complexity | High | High |
Privileges Required | None | High |
User Interaction | None | None |
Scope | Unchanged | Unchanged |
Confidentiality Impact | High | High |
Integrity Impact | High | High |
Availability Impact | High | High |
CVSS v3 Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
This flaw depends on another flaw: CVE-2021-4083
kernel: fget: check that the fd still exists after getting a ref to it
which is exploitable without any privilege (PR:N) required.
This is an interlinked flaw, and need both patches to fix this complete problem combined.
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
What can I do if my product is listed as "Will not fix"?
What can I do if my product is listed as "Fix deferred"?
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
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