CVE-2021-20216

A flaw was found in Privoxy in versions before 3.0.31. A memory leak that occurs when decompression fails unexpectedly may lead to a denial of service. The highest threat from this vulnerability is to system availability.

Weakness

The product does not properly control the allocation and maintenance of a limited resource.

Affected Software

Potential Mitigations

• Mitigation of resource exhaustion attacks requires that the target system either:

• The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.

• The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/147.html
• https://cwe.mitre.org/data/definitions/227.html
• https://cwe.mitre.org/data/definitions/492.html

References

• https://bugzilla.redhat.com/show_bug.cgi?id=1923256
• https://security.gentoo.org/glsa/202107-16
• https://www.openwall.com/lists/oss-security/2021/01/31/2
• https://www.privoxy.org/3.0.31/user-manual/whatsnew.html
• https://bugzilla.redhat.com/show_bug.cgi?id=1923256
• https://security.gentoo.org/glsa/202107-16
• https://www.openwall.com/lists/oss-security/2021/01/31/2
• https://www.privoxy.org/3.0.31/user-manual/whatsnew.html