dbcve.org
UnboundApplication · Nlnetlabs

CVE-2026-44690

HIGH · 7.5 CVSS v3.1 Developing Published 2026-07-22
Fix available
A fix is available. Upgrade to 1.25.2 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click 4 weeks old

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 · unedited
In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning that permits a malicious actor controlling a single delegated zone to poison arbitrary sibling zones under NSEC-signed parent domains. A malicious actor with one registered domain under an NSEC-signed TLD can serve malicious insecure DNS responses for unrelated sibling domains (sharing the same parent zone). Arbitrary delegations that do not exist under the parent domain and are covered by the parent's NSEC chain can be brought into insecure existence by fraudulent wildcard DS records (less labels than expected, unknown algorithm) from the malicious sibling domain. This allows the malicious actor to inject insecure wildcard records for those delegations.

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 · low confidence
Developing — this CVE was published recently and its authoritative NVD entry is still being established, so we're holding a technical summary until the source data settles rather than publish something unreliable. Re-checking after 2026-08-05.

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
UnboundApplication
Affected:>= 1.7.0, < 1.25.2

CVSS 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
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

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 · scoped
Upgrade available Upgrade to 1.25.2 or later
Fixed in 1.25.2
Recommended fix High confidence

Unbound 1.25.2 or later

  1. 1. Identify the current Unbound version by running 'unbound -V' or checking the package version.
  2. 2. If running Unbound 1.7.0 through 1.25.1, plan for an upgrade to version 1.25.2 or later.
  3. 3. Obtain the patched version from your operating system's package manager, NLnet Labs official downloads (https://www.nlnetlabs.nl/downloads/unbound/), or compile from source.
  4. 4. Before upgrading, backup the current Unbound configuration (/etc/unbound/unbound.conf or similar) and cache data if applicable.
  5. 5. Stop the Unbound service: 'sudo systemctl stop unbound' or 'sudo service unbound stop'.
  6. 6. Install the upgraded Unbound package or deploy the newly compiled binary.
  7. 7. Verify the installed version is 1.25.2 or later using 'unbound -V'.
  8. 8. Start the Unbound service: 'sudo systemctl start unbound' or 'sudo service unbound start'.

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-44690 in production — separate from our analysis above.

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