CVE-2023-40546: shim Null Dereference — Fix

Description

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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CVSS v3.1 Score

6.2

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
redhat	shim	< 15.8
fedoraproject	fedora	All
redhat	enterprise_linux	All
redhat	enterprise_linux	All

References

Advisories & Patches

https://access.redhat.com/security/cve/CVE-2023-40546 https://bugzilla.redhat.com/show_bug.cgi?id=2241796 https://access.redhat.com/security/cve/CVE-2023-40546 https://bugzilla.redhat.com/show_bug.cgi?id=2241796

Other References

https://access.redhat.com/errata/RHSA-2024:1834 https://access.redhat.com/errata/RHSA-2024:1835 https://access.redhat.com/errata/RHSA-2024:1873 https://access.redhat.com/errata/RHSA-2024:1876 https://access.redhat.com/errata/RHSA-2024:1883 https://access.redhat.com/errata/RHSA-2024:1902 https://access.redhat.com/errata/RHSA-2024:1903 https://access.redhat.com/errata/RHSA-2024:1959 https://access.redhat.com/errata/RHSA-2024:2086 https://access.redhat.com/errata/RHSA-2024:1834

Frequently Asked Questions

What is CVE-2023-40546? +

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. It has a CVSS v3.1 base score of 6.2 (MEDIUM).

How severe is CVE-2023-40546? +

CVE-2023-40546 has a CVSS v3.1 score of 6.2 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2023-40546? +

CVE-2023-40546 affects products from fedoraproject, redhat, specifically: enterprise_linux, fedora, shim. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-40546? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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