CVE-2023-20593 is a medium-severity vulnerability affecting AMD's Zen 2 CPUs, which may allow an attacker to access sensitive information under specific microarchitectural circumstances. This use-after-free issue impacts a range of systems running on Zen 2 processors, including various Ryzen, Threadripper, and Epyc models. While technical discussions and proposed solutions can be found in mailing list threads, it's important for users to stay informed and apply any available patches to protect their systems.

How do I know if I'm affected?

If you're wondering whether you're affected by the CVE-2023-20593 vulnerability, you'll need to check if you're using any of the impacted AMD products. These include various configurations of AMD Ryzen, AMD Epyc, and AMD Athlon processors, as well as Xen and Debian Linux operating systems. Keep in mind that this vulnerability is rated as medium-severity and may allow an attacker to access sensitive information under specific microarchitectural circumstances.

What should I do if I'm affected?

If you're affected by the this vulnerability, it's crucial to take action. First, apply the patch released by AMD to fix the issue. If you can't apply the patch immediately, you can temporarily set the chicken bit DE\_CFG\[9\] as a workaround, but be aware that this may impact performance. Stay informed and follow updates to ensure your system remains secure.

Is this in CISA’s Known Exploited Vulnerabilities Catalog?

The CVE-2023-20593 vulnerability is indeed listed in CISA's Known Exploited Vulnerabilities Catalog. This medium-severity issue in AMD's Zen 2 CPUs may allow an attacker to access sensitive information under specific circumstances. Although the required action is not explicitly provided, applying the patch released by AMD is recommended to address the vulnerability. It's important to stay informed and take necessary precautions to keep your system secure.

Weakness enumeration

The weakness enumeration for this vulnerability categorized as NVD-CWE-Other involves a use-after-free issue in AMD Zen 2 processors, potentially allowing unauthorized access to sensitive information. A patch and a temporary workaround, known as the "chicken bit," are available to address this vulnerability.

For more details

For a comprehensive understanding of the vulnerability, its impact, and available solutions, consult the NVD and the resources listed below.

• Open Source Software Security (oss-security) discussion

• Openwall (oss-security mailing list) discussion on patch levels

• oss-security mailing list discussion on "chicken bit fix"

• oss-security mailing list discussion on Google's security repo writeup