Vulnerability in Isc Bind 9
CVE-2026-11605
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (44.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Isc Bind 9 — versions 9.20.0, 9.21.0, 9.20.9-S1
Weakness classification (CWE)
References
- kb.isc.org/docs/cve-2026-11605 (vendor-advisory)
- downloads.isc.org/isc/bind9/9.20.26 (patch)
- downloads.isc.org/isc/bind9/9.21.24 (patch)
Frequently asked questions
- What is CVE-2026-11605?
- CVE-2026-11605 is a high-severity vulnerability in Isc Bind 9, classified under CWE-408. CVSS score: 7.5/10. Published 2026-07-22.
- How severe is CVE-2026-11605?
- High severity. CVSS v3 base score is 7.5 out of 10.