#VU63691 Time-of-check Time-of-use (TOCTOU) Race Condition in 2nd Gen AMD EPYC Processors and 3rd Gen AMD EPYC Processors - CVE-2021-26350

Vulnerability identifier: #VU63691

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-26350

CWE-ID: CWE-367

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
2nd Gen AMD EPYC Processors
Hardware solutions / Firmware
3rd Gen AMD EPYC Processors
Hardware solutions / Firmware

Vendor: AMD

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to a race condition in the System Management Unit (SMU). A local user can obtain and manipulate the address of a message port register and perform a denial of service attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

2nd Gen AMD EPYC Processors: before RomePI-SP3_1.0.0.D

3rd Gen AMD EPYC Processors: before MilanPI-SP3_1.0.0.7

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External links
https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1028

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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