CVE-2020-25687
Description
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 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.
How to fix
- thekelleys dnsmasq2.83 or later
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
- security.gentoo.org/glsa/202101-17
- debian.org/security/2021/dsa-4844
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| thekelleys dnsmasq | v < 2.83 | 2.83 |
| fedoraproject fedora | 32, 33 | — |
| debian debian_linux | 9.0, 10.0 | — |
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