High severity · published Jul 22, 2026
CVE-2026-11605
Unnecessary validation of DNSSEC signed records
7.5
CVSS
0.7%
EPSS
No
On KEV
Description
The issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all RRSIG records in an answer, even if they are not strictly needed. A query to an authoritative server/zone which returns many valid but superfluous RRSIG records causes the validator to waste disproportionate CPU time.
This issue affects BIND 9 versions 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 52% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
B9
BIND 9 · ISC
9.20.0 through 9.20.24; 9.21.0 through 9.21.23; 9.20.9-S1 through 9.20.24-S1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-11605
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-11605
downloads.isc.org
https://downloads.isc.org/isc/bind9/9.20.26
downloads.isc.org
https://downloads.isc.org/isc/bind9/9.21.24
kb.isc.org
https://kb.isc.org/docs/cve-2026-11605
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