CVE-2025-11411

Published Oct 22, 2025

Last updated 4 days ago

Overview

AI description

Automated description summarized from trusted sources.

CVE-2025-11411 is a vulnerability affecting NLnet Labs Unbound DNS resolver versions up to and including 1.24.2. It stems from Unbound's acceptance of extraneous, untrusted NS RRSets (Name Server Resource Record Sets) found in the authority section of DNS responses. These NS RRSets are typically used to update a resolver's delegation information for a DNS zone. The vulnerability can be exploited by attackers who inject malicious NS RRSets and associated address records into DNS replies, potentially through spoofed packets or fragmentation attacks. Unbound may then incorrectly update its cached delegation information, treating the injected NS RRSets as trusted in-zone data. This can lead to domain hijacking attacks. Unbound version 1.24.1 includes a fix that mitigates the possible poisoning effect by scrubbing unsolicited NS RRSets and their respective address records from replies. Version 1.24.2 includes an additional fix that scrubs unsolicited NS RRSets from YXDOMAIN and non-referral nodata replies.

Description: NLnet Labs Unbound up to and including version 1.24.2 is vulnerable to possible domain hijack attacks. Promiscuous NS RRSets that complement positive DNS replies in the authority section can be used to trick resolvers to update their delegation information for the zone. Usually these RRSets are used to update the resolver's knowledge of the zone's name servers. A malicious actor can exploit the possible poisonous effect by injecting NS RRSets (and possibly their respective address records) in a reply. This could be done for example by trying to spoof a packet or fragmentation attacks. Unbound would then proceed to update the NS RRSet data it already has since the new data has enough trust for it, i.e., in-zone data for the delegation point. Unbound 1.24.1 includes a fix that scrubs unsolicited NS RRSets (and their respective address records) from replies mitigating the possible poison effect. Unbound 1.24.2 includes an additional fix that scrubs unsolicited NS RRSets (and their respective address records) from YXDOMAIN and non-referral nodata replies, further mitigating the possible poison effect.
Source: sep@nlnetlabs.nl
NVD status: Awaiting Analysis

Risk scores

CVSS 4.0

Type: Secondary
Base score: 5.7
Impact score: -
Exploitability score: -
Vector string: CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:H/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Severity: MEDIUM

Weaknesses

sep@nlnetlabs.nl: CWE-349

Hype score: Not currently trending

References