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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-42960

41
FAUCET Score

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to poisoning via promiscuous records for the authority section. Promiscuous RRSets that complement DNS replies in the authority section can be used to trick Unbound to cache such records. If an adversary is able to attach such records in a reply (i.e., spoofed packet, fragmentation attack) he would be able to poison Unbound's cache. A malicious actor can exploit the possible poisonous effect by injecting RRSets other than NS that are also accompanied by address records in a reply, for example MX. This could be achieved by trying to spoof a reply packet or fragmentation attacks. Unbound would then accept the relative address records in the additional section and cache them if the authority RRSet has enough trust at this point, i.e., in-zone data for the delegation point. Unbound 1.25.1 contains a patch with a fix that disregards address records from the additional section if they are not explicitly relevant only to authority NS records, mitigating the possible poison effect. This is a complement fix to CVE-2025-11411.

First published: May 20, 2026Last modified: May 20, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 1.25.1CPE matchmatch criteria
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*
>= 0, < 1.25.1CPE match
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

5.7MEDIUM

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:Amber

Attack Vector
ADJACENT
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
HIGH
VS Availability
NONE
SS Confidentiality
NONE
SS Integrity
HIGH
SS Availability
HIGH
Exploit Maturity
PROOF_OF_CONCEPT
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.25%
Probability of exploitation in next 30 days
EPSS Percentile
16.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0025 is in the 1st percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (10)

microsoftpatch availablevia msrc
Product: 20736-17084Fixed in: 1.25.1-1
microsoftpatch availablevia msrc
Product: azl3 unbound 1.19.1-5 on Azure Linux 3.0Fixed in: 1.25.1-1
ubuntupatch availablevia ubuntu_usn
Product: unbound (questing)Fixed in: 1.22.0-2ubuntu2.3
ubuntupatch availablevia ubuntu_usn
Product: unbound (resolute)Fixed in: 1.24.2-1ubuntu2.1
ubuntupatch availablevia ubuntu_usn
Product: unbound (bionic)Fixed in: 1.6.7-1ubuntu2.6+esm4
ubuntupatch availablevia ubuntu_usn
Product: unbound (jammy)Fixed in: 1.13.1-1ubuntu5.15
ubuntupatch availablevia ubuntu_usn
Product: unbound (trusty)Fixed in: 1.4.22-1ubuntu4.14.04.3+esm3
ubuntupatch availablevia ubuntu_usn
Product: unbound (xenial)Fixed in: 1.5.8-1ubuntu1.1+esm3
ubuntupatch availablevia ubuntu_usn
Product: unbound (focal)Fixed in: 1.9.4-2ubuntu1.11+esm1
ubuntupatch availablevia ubuntu_usn
Product: unbound (noble)Fixed in: 1.19.2-1ubuntu3.8

Vendor Advisories (3)

ubuntuUSN-8282-2

Unbound vulnerabilities

Jun 2, 2026
ubuntuUSN-8282-1

Unbound vulnerabilities

May 20, 2026
microsoft2026-May/CVE-2026-42960Moderate

Possible cache poisoning via promiscuous records for the authority section

May 12, 2026

References

nlnetlabs.nl / downloads/unbound/CVE-2026-42960.txt
MitigationVendor Advisory