Is CVE-2021-21812 actively exploited?

No active exploitation of CVE-2021-21812 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-21812 be exploited remotely?

No. CVE-2021-21812 requires local access to exploit.

What is the CVSS score of CVE-2021-21812?

CVE-2021-21812 has a CVSS score of 7.8 (HIGH).

HOME VULNERABILITIESCVE-2021-21812

HIGH

CVE-2021-21812

CWE-787Published: August 13, 2021· Updated: Jun 17, 2026

7.8

CVSS v3.1

Official Description

A stack-based buffer overflow vulnerability exists in the command-line-parsing HandleFileArg functionality of AT&T Labs’ Xmill 0.7. Within the function HandleFileArg the argument filepattern is under control of the user who passes it in from the command line. filepattern is passed directly to strcpy copying the path provided by the user into a static sized buffer without any length checks resulting in a stack-buffer overflow. An attacker can provide malicious input to trigger these vulnerabilities.

NVD Source

Technical Analysis

CVE-2021-21812 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.8.

From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.