In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.

In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.

Affected: openEuler:24.03-LTS-SP1: unbound

Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. To help increase online privacy, Unbound supports DNS-over-TLS which allows clients to encrypt their communication. Unbound is available for most platforms such as FreeBSD, OpenBSD, NetBSD, MacOS, Linux and Microsoft Windows. Unbound is a totally free, open source software under the BSD license. It doesn't make custom builds or provide specific features to paying customers only. Security Fix(es):

In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.(CVE-2026-80225)

In NLnet Labs Unbound up to and including 1.26.0, a 255 length query name with a large TCP response can lead to a heap buffer overflow during the RRSet canonicalisation routine. This is caused by missing to add the first owner name into the buffer length check. A malicious actor operating a malicious name server or tampering with an incoming response to Unbound (canonicalisation happens before DNSSEC validation), can trigger the vulnerability.(CVE-2026-81634)

In NLnet Labs Unbound up to and including 1.26.0, a vulnerabil…

libunbound8-1.26.1-1.1 on GA media

unbound: Unbound: Denial of Service via 'serve-expired' code path bypass unbound: Unbound: ZONEMD verification bypass due to asynchronous DNSSEC resolution unbound: Unbound: Denial of Service via use-after-free in DoQ stream output buffer unbound: Unbound: Denial of Service via continuous queries on TCP/DoT connection unbound: Unbound: Heap buffer overflow via malicious DNSSEC response unbound: Unbound: Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY unbound: Unbound: Remote Code Execution Vulnerability in CNAME Synthesis unbound: Unbound: Denial of Service via use-after-free in DoH stream cleanup unbound: Unbound: Denial of Service via algorithmic complexity attacks on DNSSEC

Affected: Ubuntu:Pro:14.04:LTS: unbound, Ubuntu:Pro:16.04:LTS: unbound, Ubuntu:Pro:18.04:LTS: unbound, Ubuntu:Pro:20.04:LTS: unbound, Ubuntu:22.04:LTS: unbound, Ubuntu:24.04:LTS: unbound, Ubuntu:26.04:LTS: unbound

In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Unbound ausnutzen, um Sicherheitsmaßnahmen zu umgehen, Speicher zu korrumpieren, einen Denial of Service zu verursachen oder Code auszuführen.