CVE-2020-8616: BIND does not sufficiently limit the number of fetches performed when processing referrals

Published May 19, 2020
·
Updated

A malicious actor who intentionally exploits this lack of effective limitation on the number of fetches performed when processing referrals can, through the use of specially crafted referrals, cause a recursing server to issue a very large number of fetches in an attempt to process the referral. This has at least two potential effects: The performance of the recursing server can potentially be degraded by the additional work required to perform these fetches, and The attacker can exploit this behavior to use the recursing server as a reflector in a reflection attack with a high amplification factor.

Affected Software

21 affected componentsFixes available
ISC BIND>=9.0.0<=9.11.18
ISC BIND>=9.12.0<=9.12.4
ISC BIND>=9.13.0<=9.13.7
ISC BIND>=9.14.0<=9.14.11
ISC BIND>=9.15.0<=9.15.6
ISC BIND>=9.16.0<=9.16.2
ISC BIND>=9.17.0<=9.17.1
ISC BIND=9.12.4-p1
ISC BIND=9.12.4-p2
ISC BIND=9.9.3-s1
ISC BIND=9.10.5-s1
ISC BIND=9.10.7-s1
ISC BIND=9.11.3-s1
ISC BIND=9.11.5-s3
ISC BIND=9.11.5-s5
ISC BIND=9.11.6-s1
ISC BIND=9.11.7-s1
ISC BIND=9.11.8-s1
Debian Debian Linux=9.0
Debian Debian Linux=10.0
debian/bind9
1:9.16.50-1~deb11u21:9.16.50-1~deb11u41:9.18.41-1~deb12u11:9.18.44-1~deb12u11:9.20.15-1~deb13u11:9.20.18-1~deb13u11:9.20.20-1

Remediation

Information

Upgrade to the patched release most closely related to your current version of BIND: BIND 9.11.19 BIND 9.14.12 BIND 9.16.3 BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers. BIND 9.11.19-S1

Event History

May 19, 2020
CVE Published
via MITRE·02:05 PM
Data Sourced
via MITRE·02:05 PM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·02:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Feb 25, 2026
Data Sourced
via Ubuntu·12:54 AM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Launchpad·12:55 AM
Description
Mar 2, 2026
Data Sourced
via Debian·01:00 AM
DescriptionAffected Software

Frequently Asked Questions

1

What is CVE-2020-8616?

CVE-2020-8616 is a vulnerability that allows a malicious actor to exploit a lack of effective limitation on the number of fetches performed when processing referrals.

2

How can a malicious actor exploit CVE-2020-8616?

A malicious actor can exploit CVE-2020-8616 by using specially crafted referrals to cause a recursing server to issue a large number of fetches.

3

What is the severity of CVE-2020-8616?

CVE-2020-8616 has a severity value of 8.6, which is considered high.

4

Which software is affected by CVE-2020-8616?

The affected software includes bind9 versions 9.11.5.P4+dfsg-5.1+deb10u7, 9.11.5.P4+dfsg-5.1+deb10u9, 9.16.44-1~deb11u1, 9.18.19-1~deb12u1, and 9.19.17-1, as well as other specific versions of bind9 for different distributions.

5

How do I fix CVE-2020-8616?

To fix CVE-2020-8616, it is recommended to update to the patched versions of bind9 provided by the respective distributions.

Contact

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