Cache poisoning due to weak PRNG
CVE: CVE-2025-40780
Component: bind
CWE: CWE-338
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 was found in BIND resolvers caused by a weakness in the Pseudo Random Number Generator (PRNG). This weakness allows an attacker to potentially predict the source port and query ID used by BIND, enabling cache poisoning attacks. If successful, the attacker can inject malicious DNS responses into the resolver’s cache, causing clients to receive spoofed DNS data. Authoritative servers are generally unaffected, but recursive resolvers are exposed to this risk. Exploitation is remote and does not require user interaction.

Statement: This vulnerability in BIND 9 resolvers caused by a weakness in the Pseudo Random Number Generator (PRNG) used to select the UDP source port and DNS query (transaction) ID. Exploitation requires an attacker to correctly predict both values and race the legitimate authoritative response with a spoofed packet to perform cache poisoning. While the PRNG weakness reduces entropy and makes prediction feasible under certain conditions, this still requires precise timing, on-path or spoofing capabilities, and targeting of recursive resolvers.

The impact is limited to resolver cache integrity; it does not allow remote code execution, privilege escalation, or direct compromise of the BIND server itself. Authoritative servers are not affected. Additionally, operational mitigations such as DNSSEC validation, access control restricting recursion, and network-level packet filtering reduce real-world exploitability. No active exploits have been observed in the wild.

Because exploitation is non-trivial, requires network-level spoofing and precise timing, and only affects cache integrity without server compromise, the vulnerability is considered Important rather than Critical.

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.
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.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

To reduce risk, restrict 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.