CVE-2021-20209: 
Privoxy vulnerability analysis and mitigation

CVE-2021-20209 is a memory leak vulnerability discovered in Privoxy versions before 3.0.29. The vulnerability specifically affects the show-status CGI handler when no action files are configured. This security issue was reported in December 2020 and publicly disclosed in early 2021 (NVD, CVE).

The vulnerability has been assigned a CVSS v3.1 base score of 7.5 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. The issue is classified as CWE-401: Missing Release of Memory after Effective Lifetime. The vulnerability specifically manifests in the show-status CGI handler functionality when Privoxy is running without configured action files (NVD).

The primary impact of this vulnerability is the potential for a Denial of Service (DoS) condition through memory resource exhaustion. When exploited, the memory leak can cause the system to gradually consume more memory, potentially leading to service degradation or system instability (Ubuntu, Gentoo).

The vulnerability was fixed in Privoxy version 3.0.29. Users are advised to upgrade to this version or later. The fix was implemented through commit c62254a686 in the Privoxy repository. For systems that cannot be immediately upgraded, there is no known workaround (Privoxy, RedHat).