CVE-2021-3409
CWE-119Published: March 23, 2021· Updated: Jun 17, 2026
Official Description
The patch for CVE-2020-17380/CVE-2020-25085 was found to be ineffective, thus making QEMU vulnerable to the out-of-bounds read/write access issues previously found in the SDHCI controller emulation code. This flaw allows a malicious privileged guest to crash the QEMU process on the host, resulting in a denial of service or potential code execution. QEMU up to (including) 5.2.0 is affected by this.
Technical Analysis
CVE-2021-3409 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires high privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.
From a weakness classification perspective (CWE-119): Buffer overflow vulnerabilities can lead to arbitrary code execution or denial of service by corrupting adjacent memory.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (10)
Quick Facts
Related CVEs (CWE-119)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-3409 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts