Cyber Resilience

CVE-2020-25687

Medium

Published: 20 January 2021

Published
20 January 2021
Modified
04 November 2025
KEV Added
Patch
CVSS Score v3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.2200 95.9th percentile
Risk Priority 25 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2020-25687 is a medium-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Fedoraproject Fedora. Its CVSS base score is 5.9 (Medium).

Operationally, ranked in the top 4.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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. This flaw allows a remote attacker, who can create valid DNS…

more

replies, 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 sort_rrset() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

thekelleys
dnsmasq
≤ 2.83
fedoraproject
fedora
32, 33
debian
debian linux
10.0, 9.0

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References