dnsmasq — security advisory
A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
- Products
- dnsmasq
- Affected versions
- Not specified
- Fixed versions
- 2.83-1
- CVEs
- CVE-2020-25684
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 13:43 UTC · Revision 1
Source evidence
A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
osv:DEBIAN-CVE-2020-25684
dnsmasq
Fixed versions: 2.83-1
dnsmasq
Fixed versions: 2.83-1
dnsmasq
Fixed versions: 2.83-1
Complete source record
{
"id": "0ae48c88541d72940f2728f04d342b4817c25a1d1acbd4bce3035b7039f9461d",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2020-25684",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2020-25684",
"summary": "A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.",
"evidence": "osv:DEBIAN-CVE-2020-25684",
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"package": {
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"ecosystem": "Debian:13"
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],
"modified": "2026-10-26T12:02:40.506038568Z",
"provider": "osv",
"upstream": [
"CVE-2020-25684"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2020-25684"
]
},
"related_cves": [
{
"value": "CVE-2020-25684",
"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 452721,
"published_at": "2021-01-20T16:15:14.163+00:00"
}