NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade unboundUpgrade unbound-dracutUpgrade python3-unboundUpgrade unbound-libsUpgrade unbound-devel | Aug 2, 2026 | Jul 8, 2026 |
| Alpine Linux | — | Upgrade unbound | Jun 18, 2026 | May 20, 2026 |
| Amazon Linux Ami 2 | — | Upgrade python2-unboundUpgrade python3-unboundUpgrade unbound-libsUpgrade unbound-utilsUpgrade unbound-develUpgrade unboundUpgrade unbound-anchorUpgrade unbound-debuginfo | Jun 9, 2026 | Jun 9, 2026 |
| Amazon_linux_2023 | — | Upgrade unbound-anchor-debuginfoUpgrade unbound-libs-debuginfoUpgrade python3-unbound-debuginfoUpgrade unbound-debuginfoUpgrade unbound-utils-debuginfoUpgrade unbound-utilsUpgrade python3-unboundUpgrade unbound-debugsourceUpgrade unbound-libsUpgrade unboundUpgrade unbound-anchorUpgrade unbound-devel | May 28, 2026 | May 20, 2026 |
| Debian | — | Upgrade unbound | Jul 23, 2026 | Jul 23, 2026 |
| F5 Big Ip | — | Update F5 BIG-IP to the latest version | Jul 28, 2026 | Jul 27, 2026 |
| Freebsd | — | Upgrade FreeBSDUpgrade unbound | Jun 15, 2026 | Jun 10, 2026 |
| Redhat Openshift | — | Upgrade ose-rhel-coreos | Aug 19, 2026 | May 20, 2026 |
| Redhat_linux | — | Upgrade unbound-libs-debuginfoUpgrade unbound-develUpgrade unbound-libsUpgrade unboundUpgrade python3-unboundUpgrade unbound-utilsUpgrade unbound-dracutUpgrade unbound-anchorUpgrade unbound-debugsourceUpgrade unbound-anchor-debuginfoUpgrade unbound-debuginfoUpgrade unbound-utils-debuginfoUpgrade python3-unbound-debuginfoNo solution exists | Jul 17, 2026 | May 20, 2026 |
| Rocky_linux | — | Upgrade unbound-debuginfoUpgrade unbound-libs-debuginfoUpgrade unbound-dracutUpgrade python3-unbound-debuginfoUpgrade unbound-develUpgrade unboundUpgrade python3-unboundUpgrade unbound-debugsourceUpgrade unbound-libs | Jul 30, 2026 | Jul 28, 2026 |
| Ubuntu | — | Upgrade libunbound2 (Ubuntu Pro)Upgrade libunbound8 (Ubuntu Pro)Upgrade libunbound8Upgrade unbound (Ubuntu Pro)Upgrade unbound | May 25, 2026 | May 20, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jun 5, 2026 | May 20, 2026 |
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