Packages
- unbound - validating, recursive, caching DNS resolver
Details
It was discovered that Unbound incorrectly handled certain TCP connections.
A remote attacker could possibly use this issue to cause Unbound to consume
resources, leading to a denial of service. This issue only affected Ubuntu
26.04 LTS, Ubuntu 24.04 LTS, Ubuntu 22.04 LTS and Ubuntu 20.04 LTS.
(CVE-2026-80225)
It was discovered that Unbound incorrectly handled certain DNS responses. A
remote attacker could possibly use this issue to crash Unbound, resulting
in a denial of service. (CVE-2026-81634)
It was discovered that Unbound incorrectly handled certain DNS responses
during DNSSEC validation. A remote attacker could possibly use this issue
to cause Unbound to consume resources, leading to a denial of service.
(CVE-2026-85501)
It was discovered that Unbound incorrectly handled outgoing network ports.
A...
It was discovered that Unbound incorrectly handled certain TCP connections.
A remote attacker could possibly use this issue to cause Unbound to consume
resources, leading to a denial of service. This issue only affected Ubuntu
26.04 LTS, Ubuntu 24.04 LTS, Ubuntu 22.04 LTS and Ubuntu 20.04 LTS.
(CVE-2026-80225)
It was discovered that Unbound incorrectly handled certain DNS responses. A
remote attacker could possibly use this issue to crash Unbound, resulting
in a denial of service. (CVE-2026-81634)
It was discovered that Unbound incorrectly handled certain DNS responses
during DNSSEC validation. A remote attacker could possibly use this issue
to cause Unbound to consume resources, leading to a denial of service.
(CVE-2026-85501)
It was discovered that Unbound incorrectly handled outgoing network ports.
A remote attacker could possibly use this issue to crash Unbound, resulting
in a denial of service. (CVE-2026-50252)
It was discovered that Unbound incorrectly handled certain DNSCrypt
packets. A remote attacker could possibly use this issue to crash Unbound,
resulting in a denial of service. This issue only affected Ubuntu 26.04
LTS, Ubuntu 24.04 LTS, Ubuntu 22.04 LTS, Ubuntu 20.04 LTS and Ubuntu 18.04
LTS. (CVE-2026-40691)
It was discovered that Unbound incorrectly handled certain cached DNS
responses. A remote attacker could possibly use this issue to poison
Unbound's cache. This issue only affected Ubuntu 26.04 LTS, Ubuntu 24.04
LTS, Ubuntu 22.04 LTS and Ubuntu 20.04 LTS. (CVE-2026-44690)
It was discovered that Unbound incorrectly handled certain DNS-over-QUIC
connections. A remote attacker could possibly use this issue to cause
Unbound to consume resources, leading to a denial of service. This issue
only affected Ubuntu 26.04 LTS. (CVE-2026-32665)
It was discovered that Unbound incorrectly handled certain EDNS options. A
remote attacker could possibly use this issue to crash Unbound, resulting
in a denial of service. This issue only affected Ubuntu 26.04 LTS.
(CVE-2026-55973)
Elias Heftrig, Haya Schulmann, Niklas Vogel, and Michael Waidner discovered
that Unbound incorrectly handled validating DNSSEC messages. A remote
attacker could possibly use this issue to cause Unbound to consume
resources, leading to a denial of service. This issue only affected Ubuntu
18.04 LTS, Ubuntu 16.04 LTS and Ubuntu 14.04 LTS. (CVE-2023-50387)
It was discovered that Unbound incorrectly handled preparing an NSEC3
closest encloser proof. A remote attacker could possibly use this issue to
cause Unbound to consume resources, leading to a denial of service. This
issue only affected Ubuntu 18.04 LTS, Ubuntu 16.04 LTS and Ubuntu 14.04
LTS. (CVE-2023-50868)
Update instructions
In general, a standard system update will make all the necessary changes.
Learn more about how to get the fixes.The problem can be corrected by updating your system to the following package versions:
| Ubuntu Release | Package Version | ||
|---|---|---|---|
| 26.04 LTS resolute | libunbound8 – 1.24.2-1ubuntu2.4 | ||
| unbound – 1.24.2-1ubuntu2.4 | |||
| 24.04 LTS noble | libunbound8 – 1.19.2-1ubuntu3.12 | ||
| unbound – 1.19.2-1ubuntu3.12 | |||
| 22.04 LTS jammy | libunbound8 – 1.13.1-1ubuntu5.17 | ||
| unbound – 1.13.1-1ubuntu5.17 | |||
| 20.04 LTS focal | libunbound8 – 1.9.4-2ubuntu1.11+esm3 | ||
| unbound – 1.9.4-2ubuntu1.11+esm3 | |||
| 18.04 LTS bionic | libunbound2 – 1.6.7-1ubuntu2.6+esm6 | ||
| unbound – 1.6.7-1ubuntu2.6+esm6 | |||
| 16.04 LTS xenial | libunbound2 – 1.5.8-1ubuntu1.1+esm5 | ||
| unbound – 1.5.8-1ubuntu1.1+esm5 | |||
| 14.04 LTS trusty | libunbound2 – 1.4.22-1ubuntu4.14.04.3+esm5 | ||
| unbound – 1.4.22-1ubuntu4.14.04.3+esm5 | |||
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