How severe is CVE-2020-25684?

CVE-2020-25684 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2020-25684 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-25684?

CVE-2020-25684 primarily affects Thekelleys Dnsmasq. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-25684?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-25684 published?

CVE-2020-25684 was published on 2021-01-20 and last updated on 2026-06-17.

CVE-2020-25684

CVE-2020-25684 is a low-severity vulnerability in Thekelleys Dnsmasq with a CVSS 3.x base score of 3.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-358.

Key facts

Severity: Low (CVSS 3.x base score 3.7)
CVSS v2: 4.3
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-358
Affected product: Thekelleys Dnsmasq
Published: 2021-01-20
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-25684?: 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.
How severe is CVE-2020-25684?: CVE-2020-25684 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2020-25684 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-25684?: CVE-2020-25684 primarily affects Thekelleys Dnsmasq. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-25684?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-25684 published?: CVE-2020-25684 was published on 2021-01-20 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*

More vulnerabilities in Thekelleys Dnsmasq

CVE-2021-45957 — Critical (CVSS 9.8): Dnsmasq 2.86 has a heap-based buffer overflow in answer_request (called from FuzzAnswerTheRequest and fuzz_rfc1035.c).…
CVE-2021-45956 — Critical (CVSS 9.8): Dnsmasq 2.86 has a heap-based buffer overflow in print_mac (called from log_packet and dhcp_reply). NOTE: the vendor's…
CVE-2021-45955 — Critical (CVSS 9.8): Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.c)…
CVE-2021-45954 — Critical (CVSS 9.8): Dnsmasq 2.86 has a heap-based buffer overflow in extract_name (called from answer_auth and FuzzAuth). NOTE: the…
CVE-2021-45953 — Critical (CVSS 9.8): Dnsmasq 2.86 has a heap-based buffer overflow in extract_name (called from hash_questions and fuzz_util.c). NOTE: the…
CVE-2021-45952 — Critical (CVSS 9.8): Dnsmasq 2.86 has a heap-based buffer overflow in dhcp_reply (called from dhcp_packet and FuzzDhcp). NOTE: the vendor's…

All CVEs affecting Thekelleys Dnsmasq →

Other CWE-358 vulnerabilities

CVE-2018-0268 — Critical (CVSS 10.0): A vulnerability in the container management subsystem of Cisco Digital Network Architecture (DNA) Center could allow an…
CVE-2022-25152 — Critical (CVSS 9.9): The ITarian platform (SAAS / on-premise) offers the possibility to run code on agents via a function called procedures.…
CVE-2025-66603 — Critical (CVSS 9.8): A vulnerability has been found in FAST/TOOLS provided by Yokogawa Electric Corporation. The web server accepts the…
CVE-2025-62583 — Critical (CVSS 9.8): Whale Browser before 4.33.325.17 allows an attacker to escape the iframe sandbox in a dual-tab environment.
CVE-2023-3266 — Critical (CVSS 9.8): A non-feature complete authentication mechanism exists in the production application allowing an attacker to bypass all…
CVE-2019-6742 — Critical (CVSS 9.8): This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Samsung Galaxy S9…

Browse all CWE-358 vulnerabilities →