Skip to main content

Boteraser | Website and Server Security Solutions

🛡️ CVE-2026-42960 — unbound

🔴 CVSS 10.0 — Critical ✅ No Known Exploit CWE-349 NVD
10.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality none, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: None.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-42960 is classified as CWE-349: Acceptance of Extraneous Untrusted Data With Trusted Data. 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.

Affected software

CVE-2026-42960 is recorded against 1 package.

  • unbound (fixed in 1.25.1)

Timeline and source

Published on 20 May 2026 and last revised on 24 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

www.nlnetlabs.nl

Other advisories for this package

unbound has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-349: Acceptance of Extraneous Untrusted Data With Trusted Data) in other software:

CVE-2026-42960 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity CRITICAL
CVSS Score 10.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H
CWE CWE-349
Public Exploit ✅ No
Source NVD
Published 2026-05-20
Updated 2026-08-20
Modified 2026-07-24
Fix URL N/A

Affected Packages

Software From version Fixed in
unbound — 1.25.1

References

Exploit Protection

Are you running unbound?

CVE-2026-42960 carries CVSS 10.0 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

Check My Site For CVE-2026-42960 →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesCVECVE 2026
✓