CVE-2020-25683

Name of the Vulnerable Software and Affected Versions dnsmasq versions prior to 2.83

Description A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled. This issue is caused by the lack of length checks in the extract name() function, which could be abused to make the code execute memcpy() with a negative size in get rdata() and cause a crash in dnsmasq, resulting in a denial of service. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. The highest threat from this issue is to system availability.

Recommendations For versions prior to 2.83, update to version 2.83 or later to resolve the issue. As a temporary workaround, consider disabling DNSSEC until a patch is available. Restrict access to the extract name() function in rfc1035.c to minimize the risk of exploitation. Avoid using the get rdata() function with unvalidated input until the issue is resolved.