CVE-2026-42960
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedNLnet 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceUnbound DNS server up to 1.25.0 suffers from cache poisoning vulnerability where promiscuous records in the authority section (particularly address records in the additional section accompanying NS records) can be incorrectly cached. Attackers can exploit this via spoofed packets or fragmentation attacks to inject malicious records like MX and their associated address records into Unbound's cache.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.25.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Unbound is installedRun `unbound -h 2>&1` or `unbound-control status` to check if the Unbound resolver is present on the systemAffected if Unbound is not found on the system, this CVE does not apply
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Identify installed Unbound versionRun `unbound -h 2>&1 | head -1` or check your package manager (dpkg -l | grep unbound, rpm -qa | grep unbound) to retrieve the exact version numberAffected if The version shown is 1.25.0 or lower, placing it in the affected range
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Compare version to affected rangeReview the version number obtained. The affected range is any version prior to 1.25.1 (including 1.25.0, 1.24.x, 1.23.x, and older)Affected if The installed version is less than 1.25.1, meaning the vulnerable caching behavior is present
If Unbound is installed and the version is below 1.25.1, the system is affected by this cache poisoning vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.25.1
Upgrade Unbound to version 1.25.1 which contains the patch that disregards address records from the additional section unless explicitly relevant only to authority NS records. This is a complement fix to CVE-2025-11411.
1.25.1
- Check current Unbound version (e.g., unbound -V or unbound-control status)
- Obtain Unbound version 1.25.1 from the official NLnet Labs repository or source (www.nlnetlabs.nl)
- Stop the Unbound service
- Install the new version (using package manager or compile from source)
- Verify the upgrade was successful by checking the version
- Start the Unbound service
- Verify the service is running correctly
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42960 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-42960 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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