#VU86238 Out-of-bounds read in Shim - CVE-2023-40549

Vulnerability identifier: #VU86238

Vulnerability risk: Medium

CVSSv4.0: 2.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-40549

CWE-ID: CWE-125

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Shim
Universal components / Libraries / Libraries used by multiple products

Vendor: Red Hat Bootloader Team

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a boundary condition within the verify_buffer_authenticode()  function when parsing PE binary. A remote attacker can pass a specially crafted PE binary to the loader, trigger an out-of-bounds read error and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Shim: 0.3 - 15.7

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External links
https://access.redhat.com/security/cve/CVE-2023-40549
https://bugzilla.redhat.com/show_bug.cgi?id=2241797

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.