Excessive NSEC3 iterations cause high CPU load during insecure delegation validation
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 1.5%
exploitation probability
1.5%top 28% of all CVEs
observed exploitation
nono source reports it
If a BIND resolver is performing DNSSEC validation and encounters a maliciously crafted zone, the resolver may consume excessive CPU. Authoritative-only servers are generally unaffected, although there are circumstances where authoritative servers may make recursive queries (see: https://kb.isc.org/docs/why-does-my-authoritative-server-make-recursive-queries).
This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.46, 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.46-S1, and 9.20.9-S1 through 9.20.20-S1.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
ISC · BIND 9References
https://access.redhat.com/errata/RHSA-2026:11371https://access.redhat.com/errata/RHSA-2026:11372https://access.redhat.com/errata/RHSA-2026:15890https://access.redhat.com/errata/RHSA-2026:16060https://access.redhat.com/errata/RHSA-2026:16064https://access.redhat.com/errata/RHSA-2026:24500https://access.redhat.com/errata/RHSA-2026:24851https://access.redhat.com/errata/RHSA-2026:24934https://access.redhat.com/errata/RHSA-2026:25083https://access.redhat.com/errata/RHSA-2026:25171https://access.redhat.com/errata/RHSA-2026:25214https://access.redhat.com/errata/RHSA-2026:29110