downloads.isc.orgpatch
https://downloads.isc.org/isc/bind9/9.20.26 CVE-2026-11605
HIGH
Unnecessary validation of DNSSEC signed records
Record summary
CVE-2026-11605 has a selected CVSS score of 7.5 (high).
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.
Description source: CVE List
Exploitation context
CISA SSVC decision
ExploitationNone
AutomatableYes
Technical impactPartial
CISA Coordinator · SSVC 2.0.3 · Evaluated Jul 22, 2026 · Source: CVE List
Affected products and versions
1| Product | Source | Version range | Status |
|---|---|---|---|
BIND 9Browse ISC / BIND 9Default status: unaffected | CVE List | 9.20.0 to ≤ 9.20.24 | affected |
| 9.21.0 to ≤ 9.21.23 | affected | ||
| 9.20.9-S1 to ≤ 9.20.24-S1 | affected |
References
4downloads.isc.orgpatch
https://downloads.isc.org/isc/bind9/9.21.24 CVE-2026-11605Vendor advisory
https://kb.isc.org/docs/cve-2026-11605 nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-11605