CVE-2021-38578: insyde kernel Buffer Underwrite
Vulnerability summary
CVE-2021-38578 is a critical (CVSS 9.8) Buffer Underwrite vulnerability in insyde kernel. EPSS estimates a 1.02% chance of exploitation in the next 30 days, higher than 63.4% of scored vulnerabilities.
Not severe (CVSS 7.4, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 9 · Related 7Timeline
- 03-03-2022PublishedVulnerability first disclosed.
- 03-11-2025Last modifiedVulnerability information updated.
Description
Existing CommBuffer checks in SmmEntryPoint will not catch underflow when computing BufferSize.
CVSS metrics
5 scores · 4 sources · 2 versions- CVE.orgCNA7.4HighCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:LDiffers
- OSV · UbuntuEcosystem advisory · calculated7.4HighCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:LDiffers
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
1.02%
Chance of exploitation in the next 30 days
Percentile
63%
Versus all other CVEs
30-day change
No change 0.00 pp
From 1.02% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, administrative account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian1 product
- edk2< 2022.11-1
Insyde1 product
- kernel5.0 | 5.1 | 5.2 | 5.3 | 5.4 | 5.5
Opensuse1 product
- ovmf&distro=openSUSE Tumbleweed< 202211-1.1
Ubuntu1 product
- edk2< 0~20160408.ffea0a2c-2ubuntu0.2+esm3 | < 0~20180205.c0d9813c-2ubuntu0.3+esm2 | < 0~20191122.bd85bf54-2ubuntu3.6 | < 2022.02-3ubuntu0.22.04.3
5 vendors · 6 products
References
9 links- www.insyde.com/security-pledge/SA-2023024Third Party Advisory
