Vulnerability in Isc Bind 9
CVE-2026-97313
A recursive BIND server that receives a query with recursion desired (RD=1) followed by a non-recursive query (RD=0) may exit with an assertion failure, resulting in a denial of service. To be vulnerable, the BIND server must allow recursive queries and have at least two RPZ zones configured: one with the default setting of "recursive-only yes", and the other with "recursive-only no". This issue affects BIND 9 versions 9.16.0 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.
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
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- kb.isc.org/docs/cve-2026-97313 (vendor-advisory)
- downloads.isc.org/isc/bind9/9.20.30 (patch)
- downloads.isc.org/isc/bind9/9.21.27 (patch)
Frequently asked questions
- What is CVE-2026-97313?
- CVE-2026-97313 is a high-severity vulnerability in Isc Bind 9, classified under Reachable Assertion. CVSS score: 7.5/10. Published 2026-10-21.
- How severe is CVE-2026-97313?
- High severity. CVSS v3 base score is 7.5 out of 10.