CVE-2020-25682

NameCVE-2020-25682
DescriptionA flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from the base buffer, thus reducing, in practice, the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-2604-1, DSA-4844-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
dnsmasq (PTS)bullseye2.85-1fixed
bullseye (security)2.85-1+deb11u1fixed
bookworm2.89-1fixed
sid, trixie2.90-5fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
dnsmasqsourcestretch2.76-5+deb9u3DLA-2604-1
dnsmasqsourcebuster2.80-1+deb10u1DSA-4844-1
dnsmasqsource(unstable)2.83-1

Notes

https://www.openwall.com/lists/oss-security/2021/01/19/1
https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=4e96a4be685c9e4445f6ee79ad0b36b9119b502a

Search for package or bug name: Reporting problems