Privilege escalation in EDK2

1) Out-of-bounds write

EUVDB-ID: #VU75395

Risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-38578

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error in MdeModulePkg/Core/PiSmmCore/PiSmmCore.c. A local user trigger an out-of-bounds write and execute arbitrary code with elevated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

edk2: edk2-stable201808 - UDK2018

CPE2.3

• cpe:2.3:h:tianocore:edk2:edk2-stable201808:*:*:*:*:*:*:*
• cpe:2.3:h:tianocore:edk2:edk2-stable201811:*:*:*:*:*:*:*
• cpe:2.3:h:tianocore:edk2:edk2-stable201903:*:*:*:*:*:*:*

External links

https://bugzilla.tianocore.org/show_bug.cgi?id=3387
https://github.com/tianocore/edk2/commit/cab1f02565d3b29081dd21afb074f35fdb4e1fd6

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.