CVE-2020-35857: 
Rust vulnerability analysis and mitigation

An issue was discovered in the trust-dns-server crate before 0.18.1 for Rust, identified as CVE-2020-35857. The vulnerability involves improper handling of DNS MX and SRV null targets, which can lead to stack consumption. The issue was discovered on January 6, 2020, and was officially disclosed on October 1, 2020 (RustSec).

The vulnerability occurs when processing additional records for MX or SRV record types from the server where a zone is configured with a null target (represented as '.'). For example, an affected zone record would look like: 'no-service 86400 IN MX 0 .'. The issue has a CVSS v3.1 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, indicating it can be exploited remotely with low complexity and requires no privileges or user interaction (RustSec).

The vulnerability can lead to a stack overflow, resulting in a crash and potential denial of service (DoS) when processing additional records. This affects the availability of systems using the vulnerable versions of the trust-dns-server crate (RustSec).

The vulnerability can be exploited remotely with low complexity and requires no privileges or user interaction. It specifically occurs when processing MX or SRV records with null targets in DNS zones (RustSec).

The primary mitigation is to upgrade to version 0.18.1 or later of the trust-dns-server crate. If unable to upgrade, users should avoid using MX, SRV, or other record types with a target to the null type. It's worth noting that versions prior to 0.16.0 are unaffected as they did not support additional record processing (RustSec).