LiveActive security incident?Get immediate response
CVE Record

CVE-2020-25682: A flaw was found in dnsmasq before 2.83.

A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from the base buffer, thus reducing, in practice, the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2020-25682 is a dnsmasq heap buffer overflow. A network attacker able to create valid DNS replies could corrupt memory and possibly run code on the dnsmasq host. That threatens confidentiality, integrity, and availability for systems using vulnerable dnsmasq versions before 2.83.

Executive priority

Treat this as high priority for DNS infrastructure and embedded network devices. The vulnerability can affect core name-resolution availability and may allow code execution, but the provided evidence does not show active exploitation or KEV listing.

Technical view

The flaw is in rfc1035.c:extract_name(). It can write assuming MAXDNAME*2 bytes are available, but some paths pass an offset into the base buffer, reducing available space. Malformed-but-valid DNS reply handling before DNSSEC validation can overflow heap memory with attacker-controlled data.

Likely exposure

Exposure is likely where dnsmasq before 2.83 is used for DNS forwarding or resolution on routers, appliances, servers, or Linux distributions. The bundle names dnsmasq generally and includes Debian, Fedora, Gentoo, Red Hat, and CERT references, but it does not enumerate all downstream products.

Exploitation context

The source bundle says exploitation requires a network attacker who can create valid DNS replies. The CVE is not marked KEV, and the provided sources do not state active exploitation in the wild.

Researcher notes

The key exposure question is whether vulnerable dnsmasq code paths are reachable through DNS replies in the target deployment. The bundle provides function-level detail and distribution advisories, but not complete product coverage, exploit reliability, or proof of in-the-wild exploitation.

Mitigation direction

  • Update dnsmasq using the relevant vendor or distribution security advisory packages.
  • Prioritize systems running dnsmasq before 2.83 for remediation.
  • Review Debian, Fedora, Gentoo, Red Hat, or CERT guidance for environment-specific fixes.
  • Limit untrusted network paths to dnsmasq services where operationally feasible.
  • Monitor vendor advisories for embedded or appliance firmware using dnsmasq.

Validation and detection

  • Inventory hosts, routers, appliances, and containers running dnsmasq.
  • Confirm installed dnsmasq versions and distribution package release levels.
  • Identify internet-facing or untrusted-network DNS forwarding exposure.
  • Check whether relevant vendor advisories are applied to each platform.
  • Validate that patched systems remain on supported dnsmasq package streams.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-122: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2020-25682 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
9Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/adnsmasqdnsmasq 2.83Listed
Weakness

CWE details

CWE-122

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-122 · source CWE mapping

Heap-based Buffer Overflow

Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs