CVE-2020-25681

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in the way RRSets are sorted before validating with DNSSEC data. An attacker on the network, who can forge DNS replies such as that they are accepted as valid, could use this flaw to cause a buffer overflow with arbitrary data in a heap memory segment, possibly executing code on the machine. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Published: 2021-01-20 Last update: 2025-11-04 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-25681 is rated High Risk (71.5/100): CVSS High severity, with high exploitation likelihood (EPSS 45.36%, 98th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +25.09% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-25681

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-19 20.27% 45.36% +25.09%
2 2025-12-28 25.16% 20.27% -4.89%
3 2025-12-27 — 25.16% —

Full EPSS history (30 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-25681

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.9 [email protected]
8.3 2.0 HIGH
AV:N/AC:M/Au:N/C:P/I:P/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.6 8.5 [email protected]

Weakness enumeration for CVE-2020-25681

OS Trackers for CVE-2020-25681

vendor priority summary link
alpine — CVE-2020-25681: 1 source package rows (dnsmasq); 25 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 15. https://security.alpinelinux.org/vuln/CVE-2020-25681
debian not yet assigned CVE-2020-25681 not yet assigned priority: Debian including 1 source packages (dnsmasq), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-25681
gentoo normal CVE-2020-25681: 1 GLSA(s) (202101-17), 1 atom(s) (net-dns/dnsmasq); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-25681
redhat high — https://access.redhat.com/security/cve/CVE-2020-25681
suse high CVE-2020-25681 severity important: SUSE including 25 source package names (0.38.1.5.8.40:dnsmasq-2.78-7.6.1, 0.45.0.8.14.1:dnsmasq-2.78-7.6.1, …), 64 product×package rows across 53 product lines (Container suse/sles/15.2/virt-launcher, Container suse/sles/15.3/virt-launcher, … (53 product lines)): Fixed 64. https://www.suse.com/security/cve/CVE-2020-25681/
ubuntu medium CVE-2020-25681 medium priority: Ubuntu including 1 source packages (dnsmasq), 15 status rows across 15 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): released 14, not-affected 1. https://ubuntu.com/security/CVE-2020-25681

Affected software / configurations for CVE-2020-25681

Vendor Product Version Raw CPE
thekelleys dnsmasq < 2.83 cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2020-25681

cvelogic Threat Intelligence