What is the CVSS score of CVE-2021-27208?

CVE-2021-27208 has a CVSS 3.1 base score of 6.8 (Medium). CVSS vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.4%.

Zynq 7000S Firmware CVE-2021-27208

MEDIUM

Classic Buffer Overflow (CWE-120)

2021-03-15 cve@mitre.org

Buffer Overflow RCE Zynq 7000S Firmware Zynq 7000 Firmware

6.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

6.8 MEDIUM

AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Physical

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVE Published

Mar 15, 2021 - 13:15 nvd

MEDIUM 6.8

DescriptionNVD

When booting a Zync-7000 SOC device from nand flash memory, the nand driver in the ROM does not validate the inputs when reading in any parameters in the nand’s parameter page. IF a field read in from the parameter page is too large, this causes a buffer overflow that could lead to arbitrary code execution. Physical access and modification of the board assembly on which the Zynq-7000 SoC device mounted is needed to replace the original NAND flash memory with a NAND flash emulation device for this attack to be successful.

AnalysisAI

When booting a Zync-7000 SOC device from nand flash memory, the nand driver in the ROM does not validate the inputs when reading in any parameters in the nand’s parameter page. Rated medium severity (CVSS 6.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.

Technical ContextAI

This vulnerability is classified as Buffer Copy without Size Check (CWE-120), which allows attackers to overflow a buffer to corrupt adjacent memory. When booting a Zync-7000 SOC device from nand flash memory, the nand driver in the ROM does not validate the inputs when reading in any parameters in the nand’s parameter page. IF a field read in from the parameter page is too large, this causes a buffer overflow that could lead to arbitrary code execution. Physical access and modification of the board assembly on which the Zynq-7000 SoC device mounted is needed to replace the original NAND flash memory with a NAND flash emulation device for this attack to be successful. Affected products include: Xilinx Zynq-7000S Firmware, Xilinx Zynq-7000 Firmware.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Always validate buffer sizes before copy operations. Use bounded functions (strncpy, snprintf). Enable compiler protections.