Windows Shim ESL Variable Creation Format String Crash
CVE-2023-40546 Published on January 29, 2024

Shim: out-of-bounds read printing error messages
A flaw was found in Shim when an error happened while creating a new ESL variable. If Shim fails to create the new variable, it tries to print an error message to the user; however, the number of parameters used by the logging function doesn't match the format string used by it, leading to a crash under certain circumstances.

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Vulnerability Analysis

CVE-2023-40546 is exploitable with local system access, and does not require authorization privileges or user interaction. 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 and integrity, and a high impact on availability.

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

Timeline

Reported to Red Hat.

Made public. 113 days later.

Weakness Type

NULL Pointer Dereference

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions.


Products Associated with CVE-2023-40546

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2023-40546 are published in these products:

Red Hat Shim
 
Red Hat Enterprise Linux (RHEL)
 
Fedora Project Fedora
 
Red Hat Rhel Aus
 
Red Hat Rhel E4s
 
Red Hat Rhel Tus
 
Red Hat Rhel Eus
 

Affected Versions

Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8.2 Advanced Update Support: Red Hat Enterprise Linux 8.2 Telecommunications Update Service: Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.4 Telecommunications Update Service: Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions: Red Hat Enterprise Linux 8.6 Extended Update Support: Red Hat Enterprise Linux 8.8 Extended Update Support: Red Hat Enterprise Linux 8.8 Extended Update Support: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9.0 Extended Update Support: Red Hat Enterprise Linux 9.0 Extended Update Support: Red Hat Enterprise Linux 9.0 Extended Update Support: Red Hat Enterprise Linux 9.2 Extended Update Support:

Exploit Probability

EPSS
0.03%
Percentile
6.66%

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.