CVE-2020-25683 describes a heap-based buffer overflow in dnsmasq versions prior to 2.83, affecting various Linux distributions including Debian and Fedora. This flaw, caused by insufficient length checks, allows a remote attacker to trigger a denial of service by crafting valid DNS replies when DNSSEC is enabled. Rated Medium (CVSS 5.9), the vulnerability has a high attack complexity but does not require user interaction, primarily impacting system availability. While there is no evidence of active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), it has garnered significant community discussion and media coverage, indicating awareness and potential for future exploitation.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 2.83CPE matchmatch criteria | cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:* | ||
32CPE matchmatch criteria | cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* | ||
33CPE matchmatch criteria | cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | ||
9.0CPE matchmatch criteria | cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | ||
10.0CPE matchmatch criteria | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.
The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.
dnsmasq: heap-based buffer overflow with large memcpy in get_rdata() when DNSSEC is enabled
Jan 19, 2021A 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.
Jan 12, 2021