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Full vulnerability report · 2019
CVE-2018-5743High confidence

Limiting simultaneous TCP clients was ineffective

ISC · BIND 9

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, 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 6.46% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • 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 ISC BIND 9 and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  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: Within 30 daysRemediation target: Within 180 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.

Distribution package intelligence

Release-specific package status

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

7 package states
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
Alpine v3.23v3.23 · mainbindVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.9.14.1-r0Alpine Security Database ↗Source updated 23 Oct 2026
Alpine v3.22v3.22 · mainbindVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.9.14.1-r0Alpine Security Database ↗Source updated 23 Oct 2026
Alpine v3.21v3.21 · mainbindVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.9.14.1-r0Alpine Security Database ↗Source updated 23 Oct 2026
Debian trixietrixie · sourcebind9Vendor fix publishedDebian records a fixed source-package version for this release.1:9.11.5.P4+dfsg-4Debian Security Tracker ↗Source updated 23 Oct 2026
Debian bookwormbookworm · sourcebind9Vendor fix publishedDebian records a fixed source-package version for this release.1:9.11.5.P4+dfsg-4Debian Security Tracker ↗Source updated 23 Oct 2026
Debian forkyforky · sourcebind9Vendor fix publishedDebian records a fixed source-package version for this release.1:9.11.5.P4+dfsg-4Debian Security Tracker ↗Source updated 23 Oct 2026
Debian sidsid · sourcebind9Vendor fix publishedDebian records a fixed source-package version for this release.1:9.11.5.P4+dfsg-4Debian Security Tracker ↗Source updated 23 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-2018-5743 · CSAF 2.0 · revision 37 · interimSUSE Product Security TeamCVE-2018-5743
128 known affected

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

  • bind as component of HPE Helion OpenStack 8
  • bind-chrootenv as component of HPE Helion OpenStack 8
  • bind-doc as component of HPE Helion OpenStack 8
  • bind-libs as component of HPE Helion OpenStack 8
  • bind-libs-32bit as component of HPE Helion OpenStack 8
  • bind-utils as component of HPE Helion OpenStack 8
  • bind as component of SUSE CaaS Platform 4.0
  • bind-chrootenv as component of SUSE CaaS Platform 4.0
  • bind-devel as component of SUSE CaaS Platform 4.0
  • bind-doc as component of SUSE CaaS Platform 4.0
  • bind-utils as component of SUSE CaaS Platform 4.0
  • libbind9-1600 as component of SUSE CaaS Platform 4.0
Summary
By design, BIND is intended to limit the number of TCP clients that can be connected at any given time. The number of allowed connections is a tunable parameter which, if unset, defaults to a conservative value for most servers. Unfortunately, the code which was intended to limit the number of simultaneous connections contained an error which could be exploited to grow the number of simultaneous connections beyond this limit. Versions affected: BIND 9.9.0 -> 9.10.8-P1, 9.11.0 -> 9.11.6, 9.12.0 -> 9.12.4, 9.14.0. BIND 9 Supported Preview Edition versions 9.9.3-S1 -> 9.11.5-S3, and 9.11.5-S5. Versions 9.13.0 -> 9.13.7 of the 9.13 development branch are also affected. Versions prior to BIND 9.9.0 have not been evaluated for vulnerability to CVE-2018-5743.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
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-2018-17512

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

By design, BIND is intended to limit the number of TCP clients that can be connected at any given time. The number of allowed connections is a tunable parameter which, if unset, defaults to a conservative value for most servers. Unfortunately, the code which was intended to limit the number of simultaneous connections contained an error which could be exploited to grow the number of simultaneous connections beyond this limit. Versions affected: BIND 9.9.0 -> 9.10.8-P1, 9.11.0 -> 9.11.6, 9.12.0 -> 9.12.4, 9.14.0. BIND 9 Supported Preview Edition versions 9.9.3-S1 -> 9.11.5-S3, and 9.11.5-S5. Versions 9.13.0 -> 9.13.7 of the 9.13 development branch are also affected. Versions prior to BIND 9.9.0 have not been evaluated for vulnerability to CVE-2018-5743.

What

By design, BIND is intended to limit the number of TCP clients that can be connected at any given time. The number of allowed connections is a tunable parameter which, if unset, defaults to a conservative value for most servers. Unfortunately, the code which was intended to limit the number of simultaneous connections contained an error which could be exploited to grow the number of simultaneous connections beyond this limit. Versions affected: BIND 9.9.0 -> 9.10.8-P1, 9.11.0 -> 9.11.6, 9.12.0 -> 9.12.4, 9.14.0. BIND 9 Supported Preview Edition versions 9.9.3-S1 -> 9.11.5-S3, and 9.11.5-S5. Versions 9.13.0 -> 9.13.7 of the 9.13 development branch are also affected. Versions prior to BIND 9.9.0 have not been evaluated for vulnerability to CVE-2018-5743.

Why

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

By design, BIND is intended to limit the number of TCP clients that can be connected at any given time. The number of allowed connections is a tunable parameter which, if unset, defaults to a conservative value for most servers. Unfortunately, the code which was intended to limit the number of simultaneous connections contained an error which could be exploited to grow the number of simultaneous connections beyond this limit. Versions affected: BIND 9.9.0 -> 9.10.8-P1, 9.11.0 -> 9.11.6, 9.12.0 -> 9.12.4, 9.14.0. BIND 9 Supported Preview Edition versions 9.9.3-S1 -> 9.11.5-S3, and 9.11.5-S5. Versions 9.13.0 -> 9.13.7 of the 9.13 development branch are also affected. Versions prior to BIND 9.9.0 have not been evaluated for vulnerability to CVE-2018-5743.

Why

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

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 → Allocation of Resources Without Limits or Throttling → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
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-770 ↗

CWE-770: Allocation of Resources Without Limits or Throttling. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

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:L/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.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.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.
NetworkUnauthenticatedCWE-770
A

Official authority intelligence

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

BSI · German · WID-SEC-2025-1196Internet Systems Consortium BIND: Mehrere Schwachstellen ermöglichen Denial of Service

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Internet Systems Consortium BIND ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
BSI · German · WID-SEC-2025-1195Internet Systems Consortium BIND: Mehrere Schwachstellen ermöglichen Denial of Service

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Internet Systems Consortium BIND ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
CERT-FR · French · CERTFR-2020-AVI-015Multiples vulnérabilités dans les produits Juniper

/CVERecord?id=CVE-2017-3735 Référence CVE CVE-2018-0732 https://www.cve.org/CVERecord?id=CVE-2018-0732 Référence CVE CVE-2018-0737 https://www.cve.org/CVERecord?id=CVE-2018-0737 Référence CVE CVE-2018-0739 https://www.cve.org/CVERecord?id=CVE-2018-0739 Référence CVE CVE-2018-12126 https://www.cve.org/CVERecord?id=CVE-2018-12126 Référence CVE CVE-2018-12127 https://www.cve.org/CVERecord?id=CVE-2018-12127 Référence CVE CVE-2018-12130 https://www.cve.org/CVERecord?id=CVE-2018-12130 Référence CVE CVE-2018-1336 https://www.cve.org/CVERecord?id=CVE-2018-1336 Référence CVE CVE-2018-17972 https://www.cve.org/CVERecord?id=CVE-2018-17972 Référence CVE CVE-2018-5743 https://www.cve.org/CVERecord?id=CVE-2018-5743 Référence CVE CVE-2018-9568 https://www.cve.org/CVERecord?id=CVE-2018-9568 Référence CVE CVE-2019-1071 https://www.cve.org/CVERecord?id=CVE-2019-1071 Référence CVE CVE-2019-1073 https://www.cve.org/CVERecord?id=CVE-2019-1073 Référence CVE CVE-2019-11091 https://www.cve.org/CVERecord?id=CVE-2019-11091 Référence CVE CVE-2019-1125 https://www.cve.org/CVERecord?id=CVE-2019-1125 Référence CVE CVE-2019-11810 https://www.cve.org/CVERecord?id=CVE-2019-11810 Référence CVE CVE-2019-12735 https://www.cve.org/CVERecord?id=CVE-2019-12735 Référence CVE CVE-2019-12749 https://www.cve.org/CVERecord?id=CVE-2019-

Official advisory ↗
CERT-FR · French · CERTFR-2019-AVI-187Multiples vulnérabilités dans BIND

De multiples vulnérabilités ont été découvertes dans BIND. Elles permettent à un attaquant de provoquer un déni de service à distance.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2019-012004ISC BIND にサービス運用妨害 (DoS) の脆弱性

ISC (Internet Systems Consortium) が提供する BIND には、TCP クライアントの同時接続数の制限を迂回され、システムリソースが過度に消費されてしまう脆弱性が存在します。 BIND には、named に対して同時に接続可能な TCP クライアントの数を制限する機能があります。2019年 4月に公開された CVE-2018-5743 への対応として、TCP クライアントからの同時接続数を計算する方法が変更されました。 一方で BIND では、一つの TCP 接続で多数の DNS クエリを並列に処理することができる機能が TCP-pipelining として提供されており、デフォルトで有効に設定されています。 TCP-pipelining が有効な状態においては、一つの TCP クライアントから複数の DNS クエリが発行されると、UDP 接続時や TCP-pipelining が無効な状態における TCP 接続時と同様のシステムリソースが、受け取ったクエリ毎に消費されます。多数のクエリを含む TCP 接続がクローズされた場合、それぞれのクエリに割り当てられたリソースの開放処理が同時に発生し、サーバが一時的あるいは断続的に応答不能な状態に陥る可能性があります。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2019-002957ISC BIND 9 に複数の脆弱性

ISC BIND 9 には、次の複数の脆弱性が存在します。 *TCP クライアント接続数が設定どおりに制限されない - CVE-2018-5743 *nxdomain-redirect 機能の不備により query.c において Assertion Failure が発生する - CVE-2019-6467 *nxdomain-redirect 機能の不備により Assertion Failure が発生する - CVE-2019-6468

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.
Patch available
Affected
Fixed
Action
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 9 Oct 2019 · Last source change 17 Sept 2024, 02:26 UTC · CWE-770 · Allocation of Resources Without Limits or Throttling

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-01
European sourceENISA EUVD · EUVD-2018-17512
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    SUSE Product Security Team ↗
  2. ENISA EUVD mappingEUVD-2018-17512 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2018-17512"}
    ENISA EUVD ↗
  3. CVSS scoreCVSS version changed from 3.0 to 3.1; the displayed base score remains 7.5.
    Before
    7.5 (CVSS 3.0 · CNA · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
    After
    7.5 (CVSS 3.1 · NIST NVD · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
    NIST NVD ↗
  4. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Remediation guidance recorded
ENISA EUVD · EUVD-2018-17512↗SUSE Product Security Team security advisory↗CVE authority or vendor reference↗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-2018-5743 · cve.blacktree.nl