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Fencer Vulns
high 8.8

CVE-2022-40250 json

Stack overflow vulnerability in SMI handler on SmmSmbiosElog.

published 2022-09-20 4 y ago modified 2026-06-17 4 mo ago also EUVD-2022-43548

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

An attacker can exploit this vulnerability to elevate privileges from ring 0 to ring -2, execute arbitrary code in System Management Mode - an environment more privileged than operating system (OS) and completely isolated from it. Running arbitrary code in SMM additionally bypasses SMM-based SPI flash protections against modifications, which can help an attacker to install a firmware backdoor/implant into BIOS. Such a malicious firmware code in BIOS could persist across operating system re-installs. Additionally, this vulnerability potentially could be used by malicious actors to bypass security mechanisms provided by UEFI firmware (for example, Secure Boot and some types of memory isolation for hypervisors). This issue affects: Module name: SmmSmbiosElog SHA256: 3a8acb4f9bddccb19ec3b22b22ad97963711550f76b27b606461cd5073a93b59 Module GUID: 8e61fd6b-7a8b-404f-b83f-aa90a47cabdf This issue affects: AMI Aptio 5.x. This issue affects: AMI Aptio 5.x.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
17 mo ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • binarly.io https://www.binarly.io/advisories/BRLY-2022-016 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • AMI Aptio

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.