Existing CommBuffer checks in SmmEntryPoint will not catch underflow when computing BufferSize.
Priority MEDIUM 45CWE-124Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 2 fixed, 2 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.
Summary
Existing CommBuffer checks in SmmEntryPoint will not catch underflow when computing BufferSize.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01019 63rd percentileScored 2026-11-07
Fix Partial Red Hat: 1 advisoryRed Hat: 2 fixed, 2 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| TianoCore | EDK II | edk2-stable202208 | — | No fix listed | CNA |
- EDK II VendorTianoCore Affected edk2-stable202208 Fixed in — No fix listed CNA
CPE configurations NVD · 7
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:tianocore:edk2:*:*:*:*:*:*:*:* | up to 202202 | Vulnerable | TianoCore |
| cpe:2.3:o:insyde:kernel:5.0:*:*:*:*:*:*:* | 5.0 | Vulnerable | Insyde Software |
| cpe:2.3:o:insyde:kernel:5.1:*:*:*:*:*:*:* | 5.1 | Vulnerable | Insyde Software |
| cpe:2.3:o:insyde:kernel:5.2:*:*:*:*:*:*:* | 5.2 | Vulnerable | Insyde Software |
| cpe:2.3:o:insyde:kernel:5.3:*:*:*:*:*:*:* | 5.3 | Vulnerable | Insyde Software |
| cpe:2.3:o:insyde:kernel:5.4:*:*:*:*:*:*:* | 5.4 | Vulnerable | Insyde Software |
| cpe:2.3:o:insyde:kernel:5.5:*:*:*:*:*:*:* | 5.5 | Vulnerable | Insyde Software |
- cpe:2.3:a:tianocore:edk2:*:*:*:*:*:*:*:* Versions up to 202202 Vulnerable ·TianoCore
- cpe:2.3:o:insyde:kernel:5.0:*:*:*:*:*:*:* Versions 5.0 Vulnerable ·Insyde Software
- cpe:2.3:o:insyde:kernel:5.1:*:*:*:*:*:*:* Versions 5.1 Vulnerable ·Insyde Software
- cpe:2.3:o:insyde:kernel:5.2:*:*:*:*:*:*:* Versions 5.2 Vulnerable ·Insyde Software
- cpe:2.3:o:insyde:kernel:5.3:*:*:*:*:*:*:* Versions 5.3 Vulnerable ·Insyde Software
- cpe:2.3:o:insyde:kernel:5.4:*:*:*:*:*:*:* Versions 5.4 Vulnerable ·Insyde Software
- cpe:2.3:o:insyde:kernel:5.5:*:*:*:*:*:*:* Versions 5.5 Vulnerable ·Insyde Software
Remediation
Red Hat 1 advisory
- RHSA-2023:2165 Released 2023-05-09 · Red Hat rating Importantedk2 security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 9) edk2-20221207gitfff6d81270b5-9.el9_2, edk2-aarch64-20221207gitfff6d81270b5-9.el9_2, edk2-ovmf-20221207gitfff6d81270b5-9.el9_2
- Red Hat Enterprise Linux CRB (v. 9) edk2-aarch64-20221207gitfff6d81270b5-9.el9_2, edk2-ovmf-20221207gitfff6d81270b5-9.el9_2, edk2-tools-20221207gitfff6d81270b5-9.el9_2 +1
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2023:2165 |
| Red Hat Enterprise Linux CRB (v. 9) | Fixed | RHSA-2023:2165 |
Timeline
- 2026-10-02 Threatist record created from CVE-2021-38578
- 2026-10-03 Alias added: GHSA-grqq-3jqg-g95p
References
More TianoCore Edk2 vulnerabilities
- TI-2026-79288 Out-of-bounds write in Google Brotli decoder KEVCVSS 4.0CRITICAL 9.2
- TI-2023-24240 Buffer Overflow in EDK II Network Package CVSS 3.1HIGH 8.8
- TI-2023-24238 Infinite loop in EDK II Network Package CVSS 3.1HIGH 7.5
- TI-2023-24235 Buffer Overflow in EDK II Network Package CVSS 3.1HIGH 8.8
- TI-2023-26565 An insecure default to allow UEFI Shell in EDK2 was left enabled in Ubuntu's EDK2. CVSS 3.1MEDIUM 6.7
- TI-2023-24236 Out-of-Bounds Read in EDK II Network Package CVSS 3.1MEDIUM 6.5
Sources
- CVE-2021-38578 · CVE Program
- CVE-2021-38578 · NVD
- FIRST EPSS
- GHSA-grqq-3jqg-g95p · GitHub Advisory Database · CC BY 4.0
- CVE-2021-38578 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences