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Full vulnerability report · 2026
CVE-2026-12725High confidence

Dnsmasq: dnsmasq: heap buffer overflow in log_query() when logging unsupported ds/dnskey replies

Red Hat · Red Hat Enterprise Linux 10

5.9MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 12 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.53% for the current model date.

Compensating controls

  • Apply the linked authoritative mitigation while planning the permanent fix.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Red Hat Red Hat Enterprise Linux 10 and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 12 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

5 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcednsmasqVendor fix publishedDebian records a fixed source-package version for this release.2.91-1+deb13u2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcednsmasqAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcednsmasqVendor fix publishedDebian records a fixed source-package version for this release.2.93-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcednsmasqVendor fix publishedDebian records a fixed source-package version for this release.2.93-1Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivednsmasqVendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.2.90-2ubuntu0.4Canonical Ubuntu Security ↗Source updated 5 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-12725 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitydnsmasq: dnsmasq: heap buffer overflow in log_query() when logging unsupported DS/DNSKEY replies
11 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • dnsmasq as a component of Red Hat Enterprise Linux 10
  • dnsmasq-utils as a component of Red Hat Enterprise Linux 10
  • dnsmasq.src as a component of Red Hat Enterprise Linux 10
  • dnsmasq as a component of Red Hat Enterprise Linux 8
  • dnsmasq-utils as a component of Red Hat Enterprise Linux 8
  • dnsmasq.src as a component of Red Hat Enterprise Linux 8
  • dnsmasq as a component of Red Hat Enterprise Linux 9
  • dnsmasq-utils as a component of Red Hat Enterprise Linux 9
  • dnsmasq.src as a component of Red Hat Enterprise Linux 9
  • openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4
  • openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4
Summary
A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and query logging are both enabled, logging of DS or DNSKEY replies containing unsupported algorithm or digest types can cause dnsmasq to write past the end of an internal logging buffer. A remote attacker able to supply such a DNS response may crash the dnsmasq process, resulting in denial of service.
Remediation
Mitigate this issue by updating to a version of dnsmasq that includes the upstream fix (commit 36d081e37477027fd721fea498f3760f529034ad), or by disabling query logging if DNSSEC validation must remain enabled. After changing the configuration, restart the dnsmasq service for the changes to take effect.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-38278

No EUVD known-exploited evidence

A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and query logging are both enabled, logging of DS or DNSKEY replies containing unsupported algorithm or digest types can cause dnsmasq to write past the end of an internal logging buffer. A remote attacker able to supply such a DNS response may crash the dnsmasq process, resulting in denial of service.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
5.9 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 12 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and query logging are both enabled, logging of DS or DNSKEY replies containing unsupported algorithm or digest types can cause dnsmasq to write past the end of an internal logging buffer. A remote attacker able to supply such a DNS response may crash the dnsmasq process, resulting in denial of service.

What

A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and query logging are both enabled, logging of DS or DNSKEY replies containing unsupported algorithm or digest types can cause dnsmasq to write past the end of an internal logging buffer. A remote attacker able to supply such a DNS response may crash the dnsmasq process, resulting in denial of service.

Why

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and query logging are both enabled, logging of DS or DNSKEY replies containing unsupported algorithm or digest types can cause dnsmasq to write past the end of an internal logging buffer. A remote attacker able to supply such a DNS response may crash the dnsmasq process, resulting in denial of service.

Why

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Heap-based Buffer Overflow → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-122 ↗

CWE-122: Heap-based Buffer Overflow. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-122
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-38278Official EUVD mapping

A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and query logging are both enabled, logging of DS or DNSKEY replies containing unsupported algorithm or digest types can cause dnsmasq to write past the end of an internal logging buffer. A remote attacker able to supply such a DNS response may crash the dnsmasq process, resulting in denial of service.

Official EUVD record ↗
BSI · German · WID-SEC-2026-2036dnsmasq: Schwachstelle ermöglicht Denial of Service

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in dnsmasq ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260624Security Bulletin 24 June 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 24 June 2026, published on 24 June 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-022974レッドハット等の複数ベンダの製品におけるヒープベースのバッファオーバーフローの脆弱性

dnsmasqにヒープベースのバッファオーバーフローが発見されました。DNSSEC検証とクエリログの両方が有効になっている場合、サポートされていないアルゴリズムまたはダイジェストタイプを含むDSまたはDNSKEYの応答をログ記録するときに、dnsmasqが内部ログバッファの末尾を超えて書き込む可能性があります。このようなDNS応答を提供できるリモート攻撃者は、dnsmasqプロセスをクラッシュさせてサービス拒否（DoS）を引き起こす恐れがあります。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
Mitigate this issue by updating to a version of dnsmasq that includes the upstream fix (commit 36d081e37477027fd721fea498f3760f529034ad), or by disabling query logging if DNSSEC validation must remain enabled. After changing the configuration, restart the dnsmasq service for the changes to take effect.
04

Evidence and provenance

Published 22 Jun 2026 · Last source change 31 Aug 2026, 21:22 UTC · CWE-122 · Heap-based Buffer Overflow

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-38278
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    dnsmasq as a component of Red Hat Enterprise Linux 10; dnsmasq-utils as a component of Red Hat Enterprise Linux 10; dnsmasq.src as a component of Red Hat Enterprise Linux 10; dnsmasq as a component of Red Hat Enterprise Linux 8; dnsmasq-utils as a component of Red Hat Enterprise Linux 8; dnsmasq.src as a component of Red Hat Enterprise Linux 8; dnsmasq as a component of Red Hat Enterprise Linux 9; dnsmasq-utils as a component of Red Hat Enterprise Linux 9; dnsmasq.src as a component of Red Hat Enterprise Linux 9; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4
    After
    dnsmasq as a component of Red Hat Enterprise Linux 10; dnsmasq-utils as a component of Red Hat Enterprise Linux 10; dnsmasq.src as a component of Red Hat Enterprise Linux 10; dnsmasq as a component of Red Hat Enterprise Linux 8; dnsmasq-utils as a component of Red Hat Enterprise Linux 8; dnsmasq.src as a component of Red Hat Enterprise Linux 8; dnsmasq as a component of Red Hat Enterprise Linux 9; dnsmasq-utils as a component of Red Hat Enterprise Linux 9; dnsmasq.src as a component of Red Hat Enterprise Linux 9; openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4
    Red Hat Product Security ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    dnsmasq as a component of Red Hat Enterprise Linux 10; dnsmasq-utils as a component of Red Hat Enterprise Linux 10; dnsmasq.src as a component of Red Hat Enterprise Linux 10; dnsmasq as a component of Red Hat Enterprise Linux 8; dnsmasq-utils as a component of Red Hat Enterprise Linux 8; dnsmasq.src as a component of Red Hat Enterprise Linux 8; dnsmasq as a component of Red Hat Enterprise Linux 9; dnsmasq-utils as a component of Red Hat Enterprise Linux 9; dnsmasq.src as a component of Red Hat Enterprise Linux 9; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4; rhcos as a component of Red Hat OpenShift Container Platform 4
    After
    dnsmasq as a component of Red Hat Enterprise Linux 10; dnsmasq-utils as a component of Red Hat Enterprise Linux 10; dnsmasq.src as a component of Red Hat Enterprise Linux 10; dnsmasq as a component of Red Hat Enterprise Linux 8; dnsmasq-utils as a component of Red Hat Enterprise Linux 8; dnsmasq.src as a component of Red Hat Enterprise Linux 8; dnsmasq as a component of Red Hat Enterprise Linux 9; dnsmasq-utils as a component of Red Hat Enterprise Linux 9; dnsmasq.src as a component of Red Hat Enterprise Linux 9; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4
    Red Hat Product Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Mitigation reference recorded
ENISA EUVD · EUVD-2026-38278↗CVE authority or vendor reference↗Vendor advisory↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-12725 · cve.blacktree.nl