10

CVE-2026-42960: nlnet labs unbound

CVSS: 10.0v3.1CriticalAnalyzed
AliasesALPINE-CVE-2026-42960UBUNTU-CVE-2026-42960DEBIAN-CVE-2026-42960
Published 20-05-2026Last modified 20-05-2026
Open JSON

Vulnerability summary

CVE-2026-42960 is a critical (CVSS 10.0) vulnerability in nlnet labs unbound. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19.3% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
10.0/10
010
Critical · v3.1 (NVD)
EPSS score
0.28%
0%100%
Low · +0.03 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 6 · Related 7
OPENSUSE-SU-2026:10903-1OPENSUSE-SU-2026:21083-1RHSA-2026:20357SUSE-SU-2026:22160-1SUSE-SU-2026:22213-1SUSE-SU-2026:2369-1

Timeline

  1. 20-05-2026
    PublishedVulnerability first disclosed.
  2. 20-05-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 5 sources · 2 versions

EPSS trend

Probability

0.28%

Chance of exploitation in the next 30 days

Percentile

19%

Versus all other CVEs

30-day change

+0.03 pp

From 0.25% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.28%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Alpine1 product
  • unbound< 1.25.2-r0 | < 1.25.1-r0
Debian1 product
  • unboundAll versions (No fix recorded) | < 1.22.0-2+deb13u3 | < 1.25.1-1
Nlnet labs1 product
Nlnetlabs1 product
Ubuntu1 product
  • unbound< 1.4.22-1ubuntu4.14.04.3+esm3 | < 1.5.8-1ubuntu1.1+esm3 | < 1.6.7-1ubuntu2.6+esm4 | < 1.9.4-2ubuntu1.11+esm1 | < 1.13.1-1ubuntu5.15 | < 1.19.2-1ubuntu3.8 | < 1.22.0-2ubuntu2.3 | < 1.24.2-1ubuntu2.1

5 vendors · 5 products

References

9 links