NLnet Labs Unbound up to 1.25.0 acceptance of extraneous untrusted data with trusted data

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.6$0-$5k0.00

Summaryinfo

A vulnerability was found in NLnet Labs Unbound up to 1.25.0. It has been rated as problematic. Affected is an unknown function. The manipulation leads to acceptance of extraneous untrusted data with trusted data. This vulnerability is uniquely identified as CVE-2026-42960. The attack can only be initiated within the local network. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in NLnet Labs Unbound up to 1.25.0 and classified as problematic. This issue affects an unknown function. The manipulation with an unknown input leads to a acceptance of extraneous untrusted data with trusted data vulnerability. Using CWE to declare the problem leads to CWE-349. The product, when processing trusted data, accepts any untrusted data that is also included with the trusted data, treating the untrusted data as if it were trusted. Impacted is integrity, and availability. The summary by CVE is:

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.

The weakness was disclosed by Taofei Guo. It is possible to read the advisory at nlnetlabs.nl. The identification of this vulnerability is CVE-2026-42960 since 05/07/2026. The exploitation is known to be easy. The attack needs to approached within the local network. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 315763 (Linux Distros Unpatched Vulnerability : CVE-2026-42960), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.25.1 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (315763) and CERT Bund (WID-SEC-2026-1599). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • Red Hat Enterprise Linux
  • Fedora Linux
  • Ubuntu Linux
  • Open Source Unbound
  • cPanel cPanel/WHM

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.6

VulDB Base Score: 5.4
VulDB Temp Score: 5.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 10.0
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Acceptance of extraneous untrusted data with trusted data
CWE: CWE-349
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 315763
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-42960

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Unbound 1.25.1

Timelineinfo

05/07/2026 CVE reserved
05/20/2026 +13 days Advisory disclosed
05/20/2026 +0 days VulDB entry created
05/26/2026 +6 days VulDB entry last update

Sourcesinfo

Advisory: nlnetlabs.nl
Researcher: Taofei Guo
Status: Confirmed

CVE: CVE-2026-42960 (🔒)
GCVE (CVE): GCVE-0-2026-42960
GCVE (VulDB): GCVE-100-364847
CERT Bund: WID-SEC-2026-1599 - Unbound: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff

Entryinfo

Created: 05/20/2026 13:02
Updated: 05/26/2026 23:04
Changes: 05/20/2026 13:02 (67), 05/21/2026 06:03 (2), 05/23/2026 22:24 (12), 05/26/2026 23:04 (7)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!