CVE-2021-39275: 
Apache HTTP Server vulnerability analysis and mitigation

CVE-2021-39275 affects Apache HTTP Server 2.4.48 and earlier versions. The vulnerability was discovered in the apescapequotes() function which may write beyond the end of a buffer when given malicious input. While no included modules pass untrusted data to these functions, third-party or external modules may be affected (Apache HTTP Server).

The vulnerability exists in the apescapequotes() function which can perform an out-of-bounds write operation when processing malicious input. The issue was discovered through ClusterFuzz testing (Apache HTTP Server). The vulnerability has a CVSS base score of 9.8 (Critical) with vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (Ubuntu CVE).

A successful exploitation of this vulnerability could lead to buffer overflow, potentially allowing an attacker to execute arbitrary code or cause a denial of service condition. However, the impact is limited since no included Apache modules pass untrusted data to these functions, though third-party modules may be affected (Red Hat CVE).

The vulnerability was fixed in Apache HTTP Server version 2.4.49. Users are recommended to upgrade to this version or later. No workarounds are available - the best mitigation is to upgrade to a patched version (Apache HTTP Server).