UBUNTU-CVE-2026-77692: High severity ubuntu/isc-dhcp vulnerability

Q: What access does an attacker need to exploit this issue?

The attacker does not need privileges or user interaction. They need network access to send a crafted DNS-over-HTTPS request containing a cryptographically invalid SIG(0) record and then prematurely close the transport connection.

Q: What is the operational impact of successful exploitation?

Successful exploitation causes the named process to abort, resulting in a denial of service. The provided severity vector indicates no stated confidentiality or integrity impact.

Q: How can I determine whether an installation is affected?

Check whether the installation runs named and uses BIND 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, or 9.20.9-S1 through 9.20.27-S1. The affected Ubuntu software entries include bind9, bind9-libs, and isc-dhcp.

Published Sep 16, 2026

Updated

An attacker can cause named to abort by sending a crafted DNS-over-HTTPS request with a cryptographically invalid SIG(0) record, and then closing the transport connection prematurely. This issue affects BIND 9 versions 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, and 9.20.9-S1 through 9.20.27-S1.

Affected Software

7 affected componentsFixes available

ubuntu/isc-dhcp*

ubuntu/bind9-libs*

ubuntu/isc-dhcp*

ubuntu/bind9<1:9.20.24-1ubuntu3.1

1:9.20.24-1ubuntu3.1

ubuntu/bind9<1:9.20.24-1ubuntu0.4

1:9.20.24-1ubuntu0.4

ubuntu/isc-dhcp*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/bind9 to a version that resolves this vulnerability.
Fixed in 1:9.20.24-1ubuntu3.1
Upgrade
Upgrade ubuntu/bind9 to a version that resolves this vulnerability.
Fixed in 1:9.20.24-1ubuntu0.4

Event History

Sep 16, 2026

CVE Published

via OSV·02:17 PM

Data Sourced

via OSV·02:17 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

What access does an attacker need to exploit this issue?

The attacker does not need privileges or user interaction. They need network access to send a crafted DNS-over-HTTPS request containing a cryptographically invalid SIG(0) record and then prematurely close the transport connection.

What is the operational impact of successful exploitation?

Successful exploitation causes the named process to abort, resulting in a denial of service. The provided severity vector indicates no stated confidentiality or integrity impact.

How can I determine whether an installation is affected?

Check whether the installation runs named and uses BIND 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, or 9.20.9-S1 through 9.20.27-S1. The affected Ubuntu software entries include bind9, bind9-libs, and isc-dhcp.

UBUNTU-CVE-2026-77692: High severity ubuntu/isc-dhcp vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

What access does an attacker need to exploit this issue?

What is the operational impact of successful exploitation?

How can I determine whether an installation is affected?

Company

Resources

Contact

Frequently Asked Questions

What access does an attacker need to exploit this issue?

What is the operational impact of successful exploitation?

How can I determine whether an installation is affected?