In a query response, an attacker may send `named` multiple copies of a record that should only exist once (such as an SOA record). If the RDATA is the same on all the copies, the record is appended to the in-memory RDATA set, which can cause increased memory usage of the negative cache and possibly lead to other memory attack vectors. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

A flaw was found in BIND 9. A remote attacker could send multiple copies of a single record in a query response to the `named` service. This could lead to increased memory usage in the negative cache, potentially causing a Denial of Service (DoS) due to memory exhaustion.

This Moderate impact denial of service vulnerability in BIND 9 allows a remote attacker to exhaust memory resources by sending crafted query responses containing duplicate records. This can lead to increased memory usage in the negative cache, potentially disrupting DNS services on affected Red Hat systems running BIND. To mitigate this issue, restrict network access to the BIND `named` service to only trusted clients and networks. Implement firewall rules to limit incoming UDP/TCP port 53 traffic to known, legitimate sources. This reduces the attack surface by preventing untrusted external entities from sending crafted query responses. Red Hat Hardened Images 2026-09-16T00:00:00Z RHSA-2026:68279 bind-main-9.20.29-0.1.hum1 Red Hat Enterprise Linux 10 Fix deferred bind Red Hat Enterprise Linux 6 Not affected bind Red Hat Enterprise Linux 7 Fix deferred bind Red Hat Enterprise Linux 8 Fix deferred bind Red Hat Enterprise Linux 8 Fix deferred bind9.16 Red Hat Enterprise Linux 9 Fix deferred bind Red Hat Enterprise Linux 9 Fix deferred bind9.18 Red Hat Enterprise Linux 9 Not affected dhcp Red Hat OpenShift Container Platform 4 Fix deferred openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 4 Fix deferred openshift/ose-rhel-coreos-9 https://www.cve.org/CVERecord?id=CVE-2026-75029 https://nvd.nist.gov/vuln/detail/CVE-2026-75029 https://downloads.isc.org/isc/bind9/9.20.29 https://downloads.isc.org/isc/bind9/9.21.26 https://kb.isc.org/docs/cve-2026-75029