CVE-2020-25683
Heap-based Buffer Overflow
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. A remote attacker, who can create valid DNS replies, could use this flaw 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 get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
Official description from the CVE record, published by redhat. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
EPSS
- Score
- 0.88775 (88.8% probability)
- Percentile
- 99.8%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
Weakness (CWE)
- CWE-122Heap-based Buffer Overflow
Affected products
dnsmasq
- affected: dnsmasq 2.83
References
- jsof-tech.com/disclosures/dnspooq
- bugzilla.redhat.com/show_bug.cgi?id=1882018
- FEDORA-2021-84440e87ba (lists.fedoraproject.org)vendor-advisory
- GLSA-202101-17 (security.gentoo.org)vendor-advisory
- DSA-4844 (debian.org)vendor-advisory
- FEDORA-2021-2e4c3d5a9d (lists.fedoraproject.org)vendor-advisory
- [debian-lts-announce] 20210322 [SECURITY] [DLA 2604-1] dnsmasq security update (lists.debian.org)mailing-list
- kb.cert.org/vuls/id/434904
Timeline
- ID reserved
- Record published
- Record last updated
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About CubePath
Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:51 UTC. Sources and licenses