Cache poisoning attacks with unsolicited RRs
CVE: CVE-2025-40778
Component: bind
CWE: CWE-347
Severity: Important
CVSS v3: 8.5/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
Release date: 2025-10-22T00:00:00+00:00

A vulnerability exists in BIND’s DNS resolver logic that makes it overly permissive when accepting resource records (RRs) in responses. Under certain conditions, this flaw allows attackers to inject unsolicited or forged DNS records into the cache. This can be exploited to poison the resolver cache, redirecting clients to malicious domains or unauthorized servers.

Statement: It is classified as Important rather than Critical because its impact is limited to cache poisoning within recursive resolvers and does not allow direct code execution, privilege escalation, or service disruption. The vulnerability affects the accuracy of DNS responses, but not the availability or confidentiality of systems. Additionally, DNSSEC-enabled deployments and restricted recursive access can significantly mitigate exploitation risks. Therefore, while the flaw can misdirect network traffic and compromise trust in name resolution, it does not directly compromise the underlying server or client systems, justifying an Important — but not Critical — severity rating.

Technical Analysis:
The issue arises because BIND fails to strictly validate unsolicited resource records accompanying legitimate DNS responses. This gap allows forged recursive resolvers to be cached as valid entries. Since the attack is remote, requires no authentication, and exploits a low-complexity vector, it is highly impactful in recursive resolver environments—especially those exposed to untrusted clients or open resolvers.

Remediation:
For OpenShift Container Platform 4.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.12/html/release_notes

You may download the oc tool and use it to inspect release image metadata for the x86_64 architecture. The image digest may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

      The sha value for the release is as follows:

      (For x86_64 architecture)
      The image digest is sha256:9ea794d2dd24ff7377534edfb0447e5398a28919a84300cc79fe7bb8ae550d1b

All OpenShift Container Platform 4.12 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshift_container_platform/4.12/html-single/updating_clusters/index#updating-cluster-within-minor.
Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
For OpenShift Container Platform 4.13 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.13/html/release_notes

You may download the oc tool and use it to inspect release image metadata for x86_64 architecture. The image digest may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

      The sha value for the release is as follows:

      (For x86_64 architecture)
      The image digest is sha256:b373f9055bf22079e7baf0c7b3ea21067248932bb0ec57fa0af30c51810bbe91

All OpenShift Container Platform 4.13 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshift_container_platform/4.13/html-single/updating_clusters/index#updating-cluster-within-minor.
For OpenShift Container Platform 4.14 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata
update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.14/html/release_notes/

You may download the oc tool and use it to inspect release image metadata for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:9e91245847127c920394c66c06a2c5485a1e5e54c8254326f18c04fee139fb43

      (For s390x architecture)
      The image digest is sha256:cf49729558f112fb860b847d6a036b5545ecbf3d7ecce1107081251373be848e

      (For ppc64le architecture)
      The image digest is sha256:4bf0c14c8511361620a3d6c098f087ae6f4be7b4972314cadbabb3945f43b517

      (For aarch64 architecture)
      The image digest is sha256:279e8a5c8c3954f85de55780ac18e84cc21e052836131e921f1305094b1b4029

All OpenShift Container Platform 4.14 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshift_container_platform/4.14/html-single/updating_clusters/index#updating-cluster-cli.
For OpenShift Container Platform 4.15 see the following documentation,
which will be updated shortly for this release, for important instructions
on how to upgrade your cluster and fully apply this asynchronous errata
update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.15/html/release_notes/

You may download the oc tool and use it to inspect release image metadata
for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests
may be found at
https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:d517885ee59d46c2aca8be69fdcf916f78a510ae76a5a9f7875c1c5ab3cfc3c1

      (For s390x architecture)
      The image digest is sha256:3a4a7c87e8ca5f4e3803f8f203599b25055276a532df8e0b66ec4ec2ebc51f4c

      (For ppc64le architecture)
      The image digest is sha256:f34818181660a9f58a59e06dbe58f24de82dcbb688e5f940a41e62e08f1edf94

      (For aarch64 architecture)
      The image digest is sha256:24eeb2ea15ac709ed08df9b6f1a5d1ac334c4f7335c0ae5249e17298ab297517

All OpenShift Container Platform 4.15 users are advised to upgrade to these
updated packages and images when they are available in the appropriate
release channel. To check for available updates, use the OpenShift CLI (oc)
or web console. Instructions for upgrading a cluster are available at
https://docs.redhat.com/en/documentation/openshift_container_platform/4.15/html-single/updating_clusters/index#updating-cluster-cli.
For OpenShift Container Platform 4.16 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.16/html/release_notes/

You may download the oc tool and use it to inspect release image metadata for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:283a4968c61885c67fd17ea4d6920b665c98d53fa85fc897e067d3c4c131da3b

      (For s390x architecture)
      The image digest is sha256:5db06d746a26930aa3a8ec756f77cfcf76bcfb838327a5c71d3a0e6d920b85c6

      (For ppc64le architecture)
      The image digest is sha256:444378df90349f12c84ec1447dfb2afa40fd28e6596d8d9ab9a37b9013fc6a62

      (For aarch64 architecture)
      The image digest is sha256:c837b6a0325105e8f1487cdebf12d1b41eaa609a88f37baf986f5361ba66b08b

All OpenShift Container Platform 4.16 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshift_container_platform/4.16/html-single/updating_clusters/index#updating-cluster-cli.
For OpenShift Container Platform 4.17 see the following documentation,
which will be updated shortly for this release, for important instructions
on how to upgrade your cluster and fully apply this asynchronous errata
update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.17/html/release_notes/

You may download the oc tool and use it to inspect release image metadata
for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests
may be found at
https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:d49a4f1a4532e3822e8769a97d87f538f9101701d3997e6e883c8abff7b58a43

      (For s390x architecture)
      The image digest is sha256:baded7c05358eda3d7bc20efdc3d2b963ba80f1639c2c80b2c58bc216a1375d1

      (For ppc64le architecture)
      The image digest is sha256:4714f7f59793e8f77cc5a95eb918bd43f9a6ff31de1b35fb59b45a07f7a3f118

      (For aarch64 architecture)
      The image digest is sha256:73e2429c13a91ea4e5031c61f94c57884a7251ece3e1bbb338523e7bf8246903

All OpenShift Container Platform 4.17 users are advised to upgrade to these
updated packages and images when they are available in the appropriate
release channel. To check for available updates, use the OpenShift CLI (oc)
or web console. Instructions for upgrading a cluster are available at
https://docs.redhat.com/en/documentation/openshift_container_platform/4.17/html-single/updating_clusters/index#updating-cluster-cli.
For OpenShift Container Platform 4.18 see the following documentation,
which will be updated shortly for this release, for important instructions
on how to upgrade your cluster and fully apply this asynchronous errata
update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html/release_notes/

You may download the oc tool and use it to inspect release image metadata
for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests
may be found at
https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:64e8c4cbd3199beb1ebb8d6a208cb81fdfe62f4e52d7586033f534d35f981244

      (For s390x architecture)
      The image digest is sha256:5b964fa43873a20a66b95769bbcd6c31b028f505281fb045bb3c2ed6ca114e91

      (For ppc64le architecture)
      The image digest is sha256:2108325c5ee08249e1b0c0ad6a3daab197f5e2a1a83c8600d27c49ad0ff94307

      (For aarch64 architecture)
      The image digest is sha256:b465cef295a81eaf055c87a9af6d8ecdcc11cb1e898895d6df527eb155a7ff82

All OpenShift Container Platform 4.18 users are advised to upgrade to these
updated packages and images when they are available in the appropriate
release channel. To check for available updates, use the OpenShift CLI (oc)
or web console. Instructions for upgrading a cluster are available at
https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html-single/updating_clusters/index#updating-cluster-cli.
For OpenShift Container Platform 4.19 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this  synchronous errata update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html/release_notes/

You may download the oc tool and use it to inspect release image metadata for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:e4377ba202c97eccba15c3a428cd4e532a02d5420d5b8918cdd3284404abb1ba

      (For s390x architecture)
      The image digest is sha256:0a15e17381e77d0afdf331ae3c455e091ffd454cf69966f041abf28ad7494be9

      (For ppc64le architecture)
      The image digest is sha256:b7ec15e179936b7c832c59ee3e68c70151d16e5cb9270d1bd0f7fb6dd78e438c

      (For aarch64 architecture)
      The image digest is sha256:87fd3d95d4b0f67500c624b64a1bf69873a8ef361612fed314066f01b78677ec

All OpenShift Container Platform 4.19 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/updating_clusters/index#updating-cluster-cli.
For OpenShift Container Platform 4.20 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.20/html/release_notes/

You may download the oc tool and use it to inspect release image metadata for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

      (For x86_64 architecture)
      The image digest is sha256:2d228e6d0b5a5ef2d7eb40bc171ad44f06b990d7adb678914e5d9d047e72568d

      (For s390x architecture)
      The image digest is sha256:af6307b4034d762e4b50edfcbeff0bdd58d4530cecb960ad777fe977c5775d11

      (For ppc64le architecture)
      The image digest is sha256:7ce9923ffac52e14a5674744810689466a49479ace1525d96e1c81c6f4928eaf

      (For aarch64 architecture)
      The image digest is sha256:a1b224a91987e73d8e27b920b118fa13897c45d832fbdf38ec72d50d0e6cb8dc

All OpenShift Container Platform 4.20 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at
https://docs.redhat.com/en/documentation/openshift_container_platform/4.20/html-single/updating_clusters/index#updating-cluster-cli.
Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
The containers required to run Discovery can be installed through discovery-installer
RPM. See the official documentation for more details.
While it is not possible to eliminate risk from this vulnerability, there are several options for reducing the risk. These include restricting recursive queries to trusted or internal networks only, and apply rate limiting or firewall rules to prevent excessive or repetitive requests. Enabling DNSSEC validation helps reject forged records, while isolating recursive resolvers from authoritative servers limits the impact of potential cache poisoning. Active monitoring of CPU usage, query volume, and cache anomalies can provide early warning of abuse or attacks.