CVE-2026-44690VulnerabilityPublished 22 Jul 2026Updated 11 Nov 2026

In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field combined

Affects unboundSource GCVE Database

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Authoritative record:CVE-2026-44690· High 7.5

Not known to be exploited · CVSS 7.5 High · fixed in 1.9.4-2ubuntu1.11+esm3 : patch unbound soon.

Data as of 11 Nov 2026, 12:40 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 1.9.4-2ubuntu1.11+esm3, 1.13.1-1ubuntu5.17, 1.19.2-1ubuntu3.12 +2

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Patches and advisories

Affected software

Product	Affected	Fixed in
Ubuntu 26.10unbound`pkg:deb/ubuntu/unbound?arch=source&distro=stonking`Other threats	Affected <1.25.1-1ubuntu3.1	Fixed in 1.25.1-1ubuntu3.1
Ubuntu 26.04 LTSunbound`pkg:deb/ubuntu/unbound?arch=source&distro=resolute`Other threats	Affected <1.24.2-1ubuntu2.4	Fixed in 1.24.2-1ubuntu2.4
Ubuntu 24.04 LTSunbound`pkg:deb/ubuntu/unbound?arch=source&distro=noble`Other threats	Affected <1.19.2-1ubuntu3.12	Fixed in 1.19.2-1ubuntu3.12
Ubuntu 22.04 LTSunbound`pkg:deb/ubuntu/unbound?arch=source&distro=jammy`Other threats	Affected <1.13.1-1ubuntu5.17	Fixed in 1.13.1-1ubuntu5.17
Ubuntu Pro 20.04 LTSunbound`pkg:deb/ubuntu/unbound?arch=source&distro=esm-infra/focal`Other threats	Affected <1.9.4-2ubuntu1.11+esm3	Fixed in 1.9.4-2ubuntu1.11+esm3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and should be applied. Fixed versions include 1.9.4-2ubuntu1.11+esm3, 1.13.1-1ubuntu5.17, 1.19.2-1ubuntu3.12, 1.25.1-1ubuntu3.1, and 1.24.2-1ubuntu2.4. Users should upgrade to these or later versions to remediate the vulnerability. There is no indication that additional mitigation steps are required beyond applying the official fixes.

Description

NLnet Labs Unbound versions 1.7.0 through 1.25.1 contain a vulnerability due to insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing. This flaw allows a malicious actor controlling a single delegated zone under an NSEC-signed parent domain to poison the cache of arbitrary sibling zones. By serving fraudulent wildcard DS records, the attacker can inject insecure wildcard records for unrelated sibling delegations, effectively enabling cache poisoning attacks within the DNS resolver.

Impact

This vulnerability allows an unauthenticated attacker who controls a single delegated domain under an NSEC-signed top-level domain to perform DNS cache poisoning attacks on unrelated sibling domains. The attacker can cause the DNS resolver to accept and cache fraudulent DNS delegations and wildcard records, potentially redirecting or intercepting traffic intended for other domains. The impact is limited to integrity compromise (no confidentiality or availability impact reported). No known exploits in the wild have been reported to date.

References

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