What is the CVSS score of CVE-2023-4236?

CVE-2023-4236 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 2.1%.

Bind CVE-2023-4236

HIGH

Reachable Assertion (CWE-617)

2023-09-20 security-officer@isc.org

Denial Of Service Debian Debian Linux Fedora H300s Firmware H410c Firmware H410s Firmware H500s Firmware H700s Firmware Bind Netapp Fedoraproject Isc

7.5

CVSS 3.1 · Vendor: isc

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Vulnerability Assessment

Weakness	CWE CWE-617 ASVS 5.0 V16 - Security Logging and Error Handling Reachable assertion handling
Impact	CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 2.1% exploitation probability (EPSS)

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AnalysisAI

A flaw in the networking code handling DNS-over-TLS queries may cause named to terminate unexpectedly due to an assertion failure. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

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Technical ContextAI · show details

This vulnerability is classified under CWE-617. A flaw in the networking code handling DNS-over-TLS queries may cause named to terminate unexpectedly due to an assertion failure. This happens when internal data structures are incorrectly reused under significant DNS-over-TLS query load.18.0 through 9.18.18 and 9.18.11-S1 through 9.18.18-S1. Affected products include: Isc Bind, Fedoraproject Fedora, Debian Debian Linux, Netapp H300S Firmware, Netapp H500S Firmware. Version information: through 9.18.18.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (isc) PRIMARY 7.5 HIGH

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

Primary rating from Vendor (isc) · only source for this CVE.

CVSS VectorVendor: isc

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

DescriptionCVE.org

A flaw in the networking code handling DNS-over-TLS queries may cause named to terminate unexpectedly due to an assertion failure. This happens when internal data structures are incorrectly reused under significant DNS-over-TLS query load. This issue affects BIND 9 versions 9.18.0 through 9.18.18 and 9.18.11-S1 through 9.18.18-S1.

Threat Intelligence Overview

EPSS Score

2.1%

Top 20% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 2.1%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +2

CVSS: +38

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Denial of Service MEDIUM

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)CVE.org

cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*

cpe:2.3:a:isc:bind:9.18.11:s1:*:*:supported_preview:*:*:*

cpe:2.3:a:isc:bind:9.18.18:s1:*:*:supported_preview:*:*:*

cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*

cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*

cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*

cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:*

cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:*

cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:*

cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:*

cpe:2.3:o:netapp:h410c_firmware:-:*:*:*:*:*:*:*

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References

Advisories & patches

ADVISORY https://kb.isc.org/docs/cve-2023-4236 REF http://www.openwall.com/lists/oss-security/2023/09/20/2 REF https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IPJLLTJCSDJJII7IIZPLTBQNWP7MZH7F/ REF https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U35OARLQCPMVCBBPHWBXY5M6XJLD2TZ5/ REF https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSK5V4W4OHPM3JTJGWAQD6CZW7SFD75B/ REF https://security.netapp.com/advisory/ntap-20231013-0004/ REF https://www.debian.org/security/2023/dsa-5504

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