A 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.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-2604-1 dnsmasq security update
Debian DSA Debian DSA DSA-4844-1 dnsmasq security update
Ubuntu USN Ubuntu USN USN-4698-1 Dnsmasq vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 04 Nov 2025 20:30:00 +0000

Type Values Removed Values Added
References

cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2025-11-04T19:12:09.915Z

Reserved: 2020-09-16T00:00:00.000Z

Link: CVE-2020-25682

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-01-20T17:15:12.920

Modified: 2025-11-04T20:15:56.973

Link: CVE-2020-25682

cve-icon Redhat

Severity : Important

Publid Date: 2021-01-19T00:00:00Z

Links: CVE-2020-25682 - Bugzilla

cve-icon OpenCVE Enrichment

No data.