Local exploit: Linux kernel TUN/TAP UID init flaw bypassing network filters.
CVE-2023-4194 Published on August 7, 2023

Kernel: tap: tap_open(): correctly initialize socket uid next fix of i_uid to current_fsuid
A flaw was found in the Linux kernel's TUN/TAP functionality. This issue could allow a local user to bypass network filters and gain unauthorized access to some resources. The original patches fixing CVE-2023-1076 are incorrect or incomplete. The problem is that the following upstream commits - a096ccca6e50 ("tun: tun_chr_open(): correctly initialize socket uid"), - 66b2c338adce ("tap: tap_open(): correctly initialize socket uid"), pass "inode->i_uid" to sock_init_data_uid() as the last parameter and that turns out to not be accurate.

Vendor Advisory NVD

Vulnerability Analysis

CVE-2023-4194 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, a high impact on integrity, and no impact on availability.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
HIGH
Availability Impact:
NONE

Timeline

Reported to Red Hat.

Made public.

Weakness Type

Insecure Default Initialization of Resource

The software initializes or sets a resource with a default that is intended to be changed by the administrator, but the default is not secure.


Products Associated with CVE-2023-4194

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Linux Kernel
 
Red Hat Enterprise Linux (RHEL)
 
Fedora Project Fedora
 
Canonical Ubuntu Linux
 
Debian Linux
 
Red Hat Rhev Hypervisor
 

Affected Versions

Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Virtualization 4:

Exploit Probability

EPSS
0.01%
Percentile
0.35%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.