ELA-1261-1 dnsmasq security update

Multiple vulnerabilities

2024-11-30
Packagednsmasq
Version2.80-1+deb10u3 (buster)
Related CVEs CVE-2023-50387 CVE-2023-50868


Two vulnerabilities were found in dnsmasq, a small caching DNS proxy and DHCP/TFTP server, which could lead to denial of service by querying specially crafted DNS resource records in control of an attacker.

CVE-2023-50387

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840,
and related RFCs) allow remote attackers to cause a denial of service (CPU
consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One
of the concerns is that, when there is a zone with many DNSKEY and RRSIG
records, the protocol specification implies that an algorithm must evaluate
all combinations of DNSKEY and RRSIG records.

CVE-2023-50868

The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC
9276 guidance is skipped) allows remote attackers to cause a denial of
service (CPU consumption for SHA-1 computations) via DNSSEC responses in a
random subdomain attack, aka the "NSEC3" issue. The RFC 5155 specification
implies that an algorithm must perform thousands of iterations of a hash
function in certain situations.


For Debian 10 buster, these problems have been fixed in version 2.80-1+deb10u3.

We recommend that you upgrade your dnsmasq packages.

Further information about Extended LTS security advisories can be found in the dedicated section of our website.