---
title: "CVE-2020-8618: A buffer boundary check assertion in rdataset.c can fai"
slug: "cve-2020-8618"
description: "CVE-2020-8618: A buffer boundary check assertion in rdataset.c can fail incorrectly during zone transfer"
updated: 2020-06-17T18:13:17Z
published: 2020-06-17T18:13:17Z
---

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# CVE-2020-8618: A buffer boundary check assertion in rdataset.c can fail incorrectly during zone transfer

**CVE:** [CVE-2020-8618](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8618)

**Document version:** 2.0

**Posting date:** 17 June 2020

**Program impacted:** BIND

**Versions affected:** BIND 9.16.0 -> 9.16.3

**Severity:** Medium

**Exploitable:** Remotely

**Description:**

An assertion check in BIND (that is meant to prevent going beyond the end of a buffer when processing incoming data) can be incorrectly triggered by a large response during zone transfer.

**Impact:**

An attacker who is permitted to send zone data to a server via zone transfer can exploit this to intentionally trigger the assertion failure with a specially constructed zone, denying service to clients.

**CVSS Score:** 4.3

**CVSS Vector:** AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

For more information on the Common Vulnerability Scoring System and to obtain your specific environmental score please visit: [https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C&version=3.1](https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C&version=3.1).

**Workarounds:**

None

**Active exploits:**

We are not aware of any active exploits.

**Solution:**

Upgrade to the patched release most closely related to your current version of BIND:

- BIND 9.16.4

**Document revision history:**

1.0 Early Notification, 10 June 2020 1.1 Simplified "Exploitable" section, 17 June 2020 2.0 Public disclosure, 17 June 2020

**Related documents:**

See our [BIND 9 Security Vulnerability Matrix](https://kb.isc.org/docs/aa-00913) for a complete listing of security vulnerabilities and versions affected.

**Do you still have questions?** Questions regarding this advisory should go to [security-officer@isc.org](mailto:security-officer@isc.org). *To report a new issue, please encrypt your message using security-officer@isc.org's PGP key which can be found here: [https://www.isc.org/pgpkey/](https://www.isc.org/pgpkey/). If you are unable to use encrypted email, you may also report new issues at: [https://www.isc.org/reportbug/](https://www.isc.org/reportbug/).*

**Note:**

ISC patches only currently supported versions. When possible we indicate EOL versions affected. (For current information on which versions are actively supported, please see [https://www.isc.org/download/](https://www.isc.org/download/).)

**ISC Security Vulnerability Disclosure Policy:**

Details of our current security advisory policy and practice can be found in the ISC Software Defect and Security Vulnerability Disclosure Policy at [https://kb.isc.org/docs/aa-00861](https://kb.isc.org/docs/aa-00861).

The Knowledgebase article [https://kb.isc.org/docs/cve-2020-8618](https://kb.isc.org/docs/cve-2020-8618) is the complete and official security advisory document.

**Legal Disclaimer:**

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