CVE-2026-19630

Amplified resource exhaustion in inbound message processing

Published Oct 21, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
In a BIND resolver, inbound DNS protocol messages with a particular structure will result in additional processing, with no limit imposed by BIND. A DNS message with a maliciously large number of such structures will cause BIND to consume disproportionate amounts of CPU time and memory during processing.
This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.29, 9.21.0 through 9.21.26, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.29-S1.

Remediation

Vendor Solution

Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.30, 9.21.27, or 9.20.30-S1.


Vendor Workaround

No workarounds known.

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DSA Debian DSA DSA-6576-1 bind9 security update
Ubuntu USN Ubuntu USN USN-8969-1 Bind vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Isc bind 9
Vendors & Products Isc bind 9
Type Values Removed Values Added
First Time appeared Redhat
Redhat hummingbird
Weaknesses CWE-770
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics threat_severity

None

threat_severity

Important

Type Values Removed Values Added
Description In a BIND resolver, inbound DNS protocol messages with a particular structure will result in additional processing, with no limit imposed by BIND. A DNS message with a maliciously large number of such structures will cause BIND to consume disproportionate amounts of CPU time and memory during processing. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.29, 9.21.0 through 9.21.26, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.29-S1.
Title Amplified resource exhaustion in inbound message processing
First Time appeared Isc
Isc bind
Weaknesses CWE-407
CPEs cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
Vendors & Products Isc
Isc bind
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
isc
Published
Updated
Oct 21, 2026, 5:19 PM
Reserved
Aug 12, 2026, 3:49 PM
Status
Awaiting Analysis
Published
Oct 21, 2026, 1:18 PM
Modified
Oct 26, 2026, 9:10 PM
Severity
Important
Public date
Oct 21, 2026, 12:00 AM