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CVE Record

CVE-2026-4890: CVE-2026-4890

A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A remote attacker may crash or stall dnsmasq by sending a specially crafted DNS packet during DNSSEC validation. Successful attacks could interrupt name resolution and dependent business services. The published scoring indicates availability impact only, with no stated loss of confidentiality or integrity.

Executive priority

Treat this as an expedited availability risk where dnsmasq supports critical DNS, network access, or customer services. Prioritize exposed DNS resolvers and single points of failure. Immediate emergency response is not supported by current exploitation evidence, but inventory and vendor-guided patching should not wait for exploitation reports.

Technical view

CVE-2026-4890 is a DNSSEC-validation denial of service associated with CWE-835. It carries CVSS 3.1 score 7.5: network-accessible, low complexity, no privileges or user interaction, and high availability impact. The supplied evidence does not describe the precise vulnerable code path or a reliable affected-version range.

Likely exposure

Exposure is most likely where dnsmasq performs DNSSEC validation and processes attacker-influenced DNS packets. Internet-facing or broadly reachable DNS services warrant faster review. The bundle lists affected version "0," which is insufficient for determining actual vulnerable releases; package and appliance vendors must be consulted.

Exploitation context

The CVSS vector indicates remote, unauthenticated, low-complexity exploitation. However, the bundle reports that CVE-2026-4890 is not in CISA KEV and provides no evidence of active exploitation. Public references include vendor advisories and downstream release activity, but their detailed claims are not included here.

Researcher notes

The strongest supplied facts are the remote crafted-packet DoS, DNSSEC-validation context, CWE-835 classification, and CVSS vector. The affected-version entry "0" is not actionable, and the bundle contains no technical root-cause details. Avoid asserting specific vulnerable or fixed releases until upstream or distributor advisories are reviewed.

Mitigation direction

  • Inventory dnsmasq installations, including embedded appliances, containers, routers, and bundled products.
  • Determine whether each installation performs DNSSEC validation and accepts untrusted DNS traffic.
  • Consult upstream and distribution advisories for confirmed affected versions and corrected packages.
  • Apply vendor-supported updates identified as addressing CVE-2026-4890.
  • Pending updates, restrict DNS access to required clients and approved network paths.

Validation and detection

  • Record each dnsmasq version, package release, operating system, and supplying vendor.
  • Cross-reference every deployment against upstream or distribution guidance for CVE-2026-4890.
  • Verify DNSSEC-validation configuration and document externally or broadly reachable instances.
  • After remediation, confirm the installed package matches the vendor-designated corrected release.
  • Monitor DNS availability, unexpected process restarts, and resource exhaustion during rollout.
Prepared
Confidence
medium
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-835: 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
cve · low confidence lookup

CVE-2026-4890 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
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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: yesTechnical Impact: partial

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
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6CISA-ADP
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-4890Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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: NSEC bitmap parsing infinite loop
other:Red Hat severity ratingcvssV3_1
  • 2026-04-14T22:32:21.880Z: 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-835

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

CWE-835 · source CWE mapping

Loop with Unreachable Exit Condition ('Infinite Loop')

Loop with Unreachable Exit Condition ('Infinite Loop') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs