MediumFix available
dnsmasq — security advisory
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.
- Products
- dnsmasq
- Affected versions
- Not specified
- Fixed versions
- 2.83-r0
- CVEs
- CVE-2020-25687
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 12:08 UTC · Revision 1
Source evidence
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.
osv:ALPINE-CVE-2020-25687
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
dnsmasq
Fixed versions: 2.83-r0
Complete source record
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"modified": "2026-10-26T11:17:55.157247058Z",
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