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CVE Record

CVE-2026-4892: CVE-2026-4892

A heap-based out-of-bounds write vulnerability in the DHCPv6 implementation of dnsmasq allows local attackers to execute arbitrary code with root privileges via a crafted DHCPv6 packet.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A malicious device on a network using dnsmasq for DHCPv6 may be able to corrupt memory and take control of the service with root privileges. Successful exploitation could expose data, alter systems, or interrupt service. The supplied affected-version data is incomplete, so organizations should assess packaged and embedded dnsmasq deployments rather than rely on the listed version value.

Executive priority

Treat this as a high-priority network infrastructure issue. Rapidly identify dnsmasq DHCPv6 deployments, prioritizing untrusted local networks and critical services, then apply confirmed vendor fixes. Do not infer safety from the incomplete version data. Emergency incident response is not justified solely by this bundle because active exploitation is not established.

Technical view

CVE-2026-4892 is a heap-based out-of-bounds write in dnsmasq's DHCPv6 implementation. A crafted DHCPv6 packet can trigger memory corruption and potentially arbitrary code execution as root. CVSS 3.1 rates it 8.8 with adjacent-network access, low complexity, no privileges, and no user interaction. The bundle does not identify a reliable upstream affected or fixed version range.

Likely exposure

Exposure is most likely where dnsmasq provides DHCPv6 and accepts packets from attacker-accessible local network segments. Internet-only reachability is not indicated by the CVSS vector. Appliances, distributions, and bundled products may include dnsmasq, but the supplied version value, "0," is insufficient for determining vulnerability.

Exploitation context

The supplied sources do not establish active exploitation, and the CVE is not listed as KEV in the bundle. Exploitation requires adjacent-network access rather than authenticated local system access. The stated impact is root-level code execution, making compromised network segments and untrusted client networks important threat scenarios.

Researcher notes

CWE-122 and the CVSS vector support heap corruption reachable from an adjacent network without authentication or user interaction. Root execution is reported, but the bundle lacks technical root-cause detail, affected code paths, reliable version boundaries, and an upstream fixed version. Avoid extending conclusions beyond DHCPv6-enabled deployments until vendor advisories provide precise package status.

Mitigation direction

  • Check dnsmasq, operating-system, and appliance vendor advisories for confirmed affected and fixed package versions.
  • Apply vendor updates that explicitly address CVE-2026-4892, including applicable distribution or embedded-product releases.
  • Prioritize DHCPv6 servers reachable from untrusted, guest, branch, or otherwise weakly controlled network segments.
  • Review vendor guidance before changing DHCPv6 availability or applying compensating controls.

Validation and detection

  • Inventory systems, appliances, and bundled products that install or embed dnsmasq.
  • Determine whether each deployment enables dnsmasq DHCPv6 and which network segments can send it packets.
  • Compare installed package builds against applicable vendor advisories and errata for CVE-2026-4892.
  • After remediation, verify the deployed package build matches the vendor's fixed release.
  • Monitor affected network segments and hosts for unexplained dnsmasq crashes or privileged-service anomalies.
Prepared
Confidence
medium
Sources
8

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.

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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-2026-4892 mapping review

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

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

2CVSS vectors
5Timeline events
2ADP providers
15Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.8CVSS 3.1HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H2.85.9redhat-SADP
8.4CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H2.55.9CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2026-4892Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Reported to Red Hat.

  3. ADP timelineredhat-SADP

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
redhat-SADPdnsmasq: DHCPv6 CLID buffer overflow in helper process
other:Red Hat severity ratingcvssV3_1
  • 2026-04-14T22:44:58.432Z: Reported to Red Hat.
  • 2026-05-09T00:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
dnsmasqdnsmasq0Listed
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