# CVE-2025-5994: Cache poisoning via the ECS-enabled Rebirthday Attack CVE-2025-5994 is fixed in 15 products on 1 platform, first by RHSA-2025:12064, released July 16, 2025. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2025-5994 - Priority: High - CVSS: 7.5 (Medium) - EPSS: 0.0022 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jul 16, 2025 - Weakness: Acceptance of Extraneous Untrusted Data With Trusted Data - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-5994 ## Description A multi-vendor cache poisoning vulnerability named 'Rebirthday Attack' hasbeen discovered in caching resolvers that support EDNS Client Subnet (ECS).Unbound is also vulnerable when compiled with ECS support, i.e.,'--enable-subnet', AND configured to send ECS information along withqueries to upstream name servers, i.e., at least one of the'send-client-subnet', 'client-subnet-zone' or'client-subnet-always-forward' options is used. Resolvers supporting ECSneed to segregate outgoing queries to accommodate for different outgoingECS information. This re-opens up resolvers to a birthday paradox attack(Rebirthday Attack) that tries to match the DNS transaction ID in order tocache non-ECS poisonous replies. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | libunbound8 Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.11 | [libunbound8 1.13.1-1ubuntu5.11](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libunbound8-1.13.1-1ubuntu5.11.md) | Jul 16, 2025 | | Linux | libunbound8 Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.5 | [libunbound8 1.19.2-1ubuntu3.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libunbound8-1.19.2-1ubuntu3.5.md) | Jul 16, 2025 | | Linux | libunbound8 Ubuntu 25.04 (plucky) | 1.22.0-1ubuntu1.1 | [libunbound8 1.22.0-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libunbound8-1.22.0-1ubuntu1.1.md) | Jul 17, 2025 | | Linux | libunbound8 Ubuntu 25.10 (questing) | 1.22.0-2ubuntu1 | [libunbound8 1.22.0-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libunbound8-1.22.0-2ubuntu1.md) | Jul 16, 2025 | | Linux | python3-unbound RHEL 8 | 0:1.16.2-5.9.el8_10 | [RHSA-2025:11884](https://patchblox.com/security/data/fix/linux/rhsa-2025-11884.md) | Jul 28, 2025 | | Linux | python3-unbound RHEL 9 | 0:1.16.2-19.el9_6.1 | [RHSA-2025:11849](https://patchblox.com/security/data/fix/linux/rhsa-2025-11849.md) | Jul 28, 2025 | | Linux | python3-unbound Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.11 | [python3-unbound 1.13.1-1ubuntu5.11](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-unbound-1.13.1-1ubuntu5.11.md) | Jul 16, 2025 | | Linux | python3-unbound Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.5 | [python3-unbound 1.19.2-1ubuntu3.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-unbound-1.19.2-1ubuntu3.5.md) | Jul 16, 2025 | | Linux | python3-unbound Ubuntu 25.04 (plucky) | 1.22.0-1ubuntu1.1 | [python3-unbound 1.22.0-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-python3-unbound-1.22.0-1ubuntu1.1.md) | Jul 17, 2025 | | Linux | python3-unbound Ubuntu 25.10 (questing) | 1.22.0-2ubuntu1 | [python3-unbound 1.22.0-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-python3-unbound-1.22.0-2ubuntu1.md) | Jul 16, 2025 | | Linux | python3-unbound almalinux 10 | 1.20.0-12.el10_0 | [ALSA-2025:12064](https://patchblox.com/security/data/fix/linux/alsa-2025-12064.md) | Jul 29, 2025 | | Linux | python3-unbound almalinux 8 | 1.16.2-5.9.el8_10 | [ALSA-2025:11884](https://patchblox.com/security/data/fix/linux/alsa-2025-11884.md) | Jul 28, 2025 | | Linux | python3-unbound almalinux 9 | 1.16.2-19.el9_6.1 | [ALSA-2025:11849](https://patchblox.com/security/data/fix/linux/alsa-2025-11849.md) | Jul 28, 2025 | | Linux | python3-unbound amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | python3-unbound ol 10 | 0:1.20.0-12.el10_0 | [ELSA-2025-12064](https://patchblox.com/security/data/fix/linux/elsa-2025-12064.md) | Jul 29, 2025 | | Linux | python3-unbound ol 8 | 0:1.16.2-5.9.el8_10 | [ELSA-2025-11884](https://patchblox.com/security/data/fix/linux/elsa-2025-11884.md) | Jul 28, 2025 | | Linux | python3-unbound ol 9 | 0:1.16.2-19.el9_6.1 | [ELSA-2025-11849](https://patchblox.com/security/data/fix/linux/elsa-2025-11849.md) | Jul 28, 2025 | | Linux | python3-unbound-debuginfo amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound Debian 12.15 (bookworm) | 1.17.1-2+deb12u3 | [DEBIAN-CVE-2025-5994](https://patchblox.com/security/data/fix/linux/debian-cve-2025-5994.md) | Jul 16, 2025 | | Linux | unbound Debian 13.5 (trixie) | 1.22.0-2 | [DEBIAN-CVE-2025-5994](https://patchblox.com/security/data/fix/linux/debian-cve-2025-5994.md) | Jul 16, 2025 | | Linux | unbound Debian 14 | 1.22.0-2 | [DEBIAN-CVE-2025-5994](https://patchblox.com/security/data/fix/linux/debian-cve-2025-5994.md) | Jul 16, 2025 | | Linux | unbound RHEL 10 | 1.20.0-12.el10_0 | [RHSA-2025:12064](https://patchblox.com/security/data/fix/linux/rhsa-2025-12064.md) | Jul 16, 2025 | | Linux | unbound RHEL 8 | 0:1.16.2-5.9.el8_10 | [RHSA-2025:11884](https://patchblox.com/security/data/fix/linux/rhsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound RHEL 9 | 0:1.16.2-19.el9_6.1 | [RHSA-2025:11849](https://patchblox.com/security/data/fix/linux/rhsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.11 | [unbound 1.13.1-1ubuntu5.11](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-unbound-1.13.1-1ubuntu5.11.md) | Jul 16, 2025 | | Linux | unbound Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.5 | [unbound 1.19.2-1ubuntu3.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-unbound-1.19.2-1ubuntu3.5.md) | Jul 16, 2025 | | Linux | unbound Ubuntu 25.04 (plucky) | 1.22.0-1ubuntu1.1 | [unbound 1.22.0-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-unbound-1.22.0-1ubuntu1.1.md) | Jul 17, 2025 | | Linux | unbound Ubuntu 25.10 (questing) | 1.22.0-2ubuntu1 | [unbound 1.22.0-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-unbound-1.22.0-2ubuntu1.md) | Jul 16, 2025 | | Linux | unbound almalinux 10 | 1.20.0-12.el10_0 | [ALSA-2025:12064](https://patchblox.com/security/data/fix/linux/alsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound almalinux 8 | 1.16.2-5.9.el8_10 | [ALSA-2025:11884](https://patchblox.com/security/data/fix/linux/alsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound almalinux 9 | 1.16.2-19.el9_6.1 | [ALSA-2025:11849](https://patchblox.com/security/data/fix/linux/alsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound ol 10 | 0:1.20.0-12.el10_0 | [ELSA-2025-12064](https://patchblox.com/security/data/fix/linux/elsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound ol 8 | 0:1.16.2-5.9.el8_10 | [ELSA-2025-11884](https://patchblox.com/security/data/fix/linux/elsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound ol 9 | 0:1.16.2-19.el9_6.1 | [ELSA-2025-11849](https://patchblox.com/security/data/fix/linux/elsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound rocky 8 | 0:1.16.2-5.9.el8 | [RLSA-2025:11884](https://patchblox.com/security/data/fix/linux/rlsa-2025-11884.md) | May 29, 2026 | | Linux | unbound rocky 9 | 0:1.16.2-19.el9_6.1 | [RLSA-2025:11849](https://patchblox.com/security/data/fix/linux/rlsa-2025-11849.md) | Oct 4, 2025 | | Linux | unbound-anchor Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.11 | [unbound-anchor 1.13.1-1ubuntu5.11](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-unbound-anchor-1.13.1-1ubuntu5.11.md) | Jul 16, 2025 | | Linux | unbound-anchor Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.5 | [unbound-anchor 1.19.2-1ubuntu3.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-unbound-anchor-1.19.2-1ubuntu3.5.md) | Jul 16, 2025 | | Linux | unbound-anchor Ubuntu 25.04 (plucky) | 1.22.0-1ubuntu1.1 | [unbound-anchor 1.22.0-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-unbound-anchor-1.22.0-1ubuntu1.1.md) | Jul 17, 2025 | | Linux | unbound-anchor Ubuntu 25.10 (questing) | 1.22.0-2ubuntu1 | [unbound-anchor 1.22.0-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-unbound-anchor-1.22.0-2ubuntu1.md) | Jul 16, 2025 | | Linux | unbound-anchor almalinux 10 | 1.20.0-12.el10_0 | [ALSA-2025:12064](https://patchblox.com/security/data/fix/linux/alsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound-anchor amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound-anchor ol 10 | 0:1.20.0-12.el10_0 | [ELSA-2025-12064](https://patchblox.com/security/data/fix/linux/elsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound-anchor-debuginfo amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound-debuginfo amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound-debugsource amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound-devel RHEL 8 | 0:1.16.2-5.9.el8_10 | [RHSA-2025:11884](https://patchblox.com/security/data/fix/linux/rhsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound-devel RHEL 9 | 0:1.16.2-19.el9_6.1 | [RHSA-2025:11849](https://patchblox.com/security/data/fix/linux/rhsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-devel almalinux 10 | 1.20.0-12.el10_0 | [ALSA-2025:12064](https://patchblox.com/security/data/fix/linux/alsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound-devel almalinux 8 | 1.16.2-5.9.el8_10 | [ALSA-2025:11884](https://patchblox.com/security/data/fix/linux/alsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound-devel almalinux 9 | 1.16.2-19.el9_6.1 | [ALSA-2025:11849](https://patchblox.com/security/data/fix/linux/alsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-devel amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound-devel ol 10 | 0:1.20.0-12.el10_0 | [ELSA-2025-12064](https://patchblox.com/security/data/fix/linux/elsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound-devel ol 8 | 0:1.16.2-5.9.el8_10 | [ELSA-2025-11884](https://patchblox.com/security/data/fix/linux/elsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound-devel ol 9 | 0:1.16.2-19.el9_6.1 | [ELSA-2025-11849](https://patchblox.com/security/data/fix/linux/elsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-dracut RHEL 9 | 0:1.16.2-19.el9_6.1 | [RHSA-2025:11849](https://patchblox.com/security/data/fix/linux/rhsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-dracut almalinux 10 | 1.20.0-12.el10_0 | [ALSA-2025:12064](https://patchblox.com/security/data/fix/linux/alsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound-dracut almalinux 9 | 1.16.2-19.el9_6.1 | [ALSA-2025:11849](https://patchblox.com/security/data/fix/linux/alsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-dracut ol 10 | 0:1.20.0-12.el10_0 | [ELSA-2025-12064](https://patchblox.com/security/data/fix/linux/elsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound-dracut ol 9 | 0:1.16.2-19.el9_6.1 | [ELSA-2025-11849](https://patchblox.com/security/data/fix/linux/elsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-host Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.11 | [unbound-host 1.13.1-1ubuntu5.11](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-unbound-host-1.13.1-1ubuntu5.11.md) | Jul 16, 2025 | | Linux | unbound-host Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.5 | [unbound-host 1.19.2-1ubuntu3.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-unbound-host-1.19.2-1ubuntu3.5.md) | Jul 16, 2025 | | Linux | unbound-host Ubuntu 25.04 (plucky) | 1.22.0-1ubuntu1.1 | [unbound-host 1.22.0-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-unbound-host-1.22.0-1ubuntu1.1.md) | Jul 17, 2025 | | Linux | unbound-host Ubuntu 25.10 (questing) | 1.22.0-2ubuntu1 | [unbound-host 1.22.0-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-unbound-host-1.22.0-2ubuntu1.md) | Jul 16, 2025 | | Linux | unbound-libs RHEL 8 | 0:1.16.2-5.9.el8_10 | [RHSA-2025:11884](https://patchblox.com/security/data/fix/linux/rhsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound-libs RHEL 9 | 0:1.16.2-19.el9_6.1 | [RHSA-2025:11849](https://patchblox.com/security/data/fix/linux/rhsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-libs almalinux 10 | 1.20.0-12.el10_0 | [ALSA-2025:12064](https://patchblox.com/security/data/fix/linux/alsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound-libs almalinux 8 | 1.16.2-5.9.el8_10 | [ALSA-2025:11884](https://patchblox.com/security/data/fix/linux/alsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound-libs almalinux 9 | 1.16.2-19.el9_6.1 | [ALSA-2025:11849](https://patchblox.com/security/data/fix/linux/alsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-libs amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound-libs ol 10 | 0:1.20.0-12.el10_0 | [ELSA-2025-12064](https://patchblox.com/security/data/fix/linux/elsa-2025-12064.md) | Jul 29, 2025 | | Linux | unbound-libs ol 8 | 0:1.16.2-5.9.el8_10 | [ELSA-2025-11884](https://patchblox.com/security/data/fix/linux/elsa-2025-11884.md) | Jul 28, 2025 | | Linux | unbound-libs ol 9 | 0:1.16.2-19.el9_6.1 | [ELSA-2025-11849](https://patchblox.com/security/data/fix/linux/elsa-2025-11849.md) | Jul 28, 2025 | | Linux | unbound-libs-debuginfo amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound-utils amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | | Linux | unbound-utils-debuginfo amzn 2023 | 1.17.1-1.amzn2023.0.8 | [ALAS2023-2025-1122](https://patchblox.com/security/data/fix/linux/alas2023-2025-1122.md) | Jul 29, 2025 | --- Data as of 2026-11-08T06:59:42Z UTC. 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