CVE-2020-25683

Affected: dnsmasq

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), 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. The highest threat from this vulnerability is to system availability.

USN-4698-1 — dnsmasq vulnerabilities

Affected: Ubuntu:16.04:LTS: dnsmasq, Ubuntu:18.04:LTS: dnsmasq, Ubuntu:20.04:LTS: dnsmasq

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled memory when sorting RRsets. A remote attacker could use this issue to cause Dnsmasq to hang, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-25681, CVE-2020-25687)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled extracting certain names. A remote attacker could use this issue to cause Dnsmasq to hang, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-25682, CVE-2020-25683)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly implemented address/port checks. A remote attacker could use this issue to perform a cache poisoning attack. (CVE-2020-25684)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly implemented query resource name checks. A remote attacker could use this issue to perform a cache poisoning attack. (CVE-2020-25685)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled multiple query requests for the same resource name. A remote attacker could use this issue to perform a cache poisoning attack. (CVE-2020-25686)

It was discovered that Dnsmasq incorrectly handled memory during DHCP response creation. A remote attacker could possibly use this issue to cause Dnsmasq to consume resources, leading to a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2019-14834)

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CVE-2020-25683

USN-4698-1 — dnsmasq vulnerabilities