FedoraOperating system · Fedoraproject
CVE-2019-10190
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 · uneditedA vulnerability was discovered in DNS resolver component of knot resolver through version 3.2.0 before 4.1.0 which allows remote attackers to bypass DNSSEC validation for non-existence answer. NXDOMAIN answer would get passed through to the client even if its DNSSEC validation failed, instead of sending a SERVFAIL packet. Caching is not affected by this particular bug but see CVE-2019-10191.
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 confidenceIn knot resolver versions before 4.1.0, the DNS resolver's DNSSEC validation logic fails to properly handle non-existence answers (NXDOMAIN). When DNSSEC validation fails for an NXDOMAIN response, the resolver incorrectly forwards the response to the client instead of generating a SERVFAIL, allowing remote attackers to potentially spoof DNS responses and cause clients to believe a domain does not exist.
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
FedoraOperating system
= 29= 30<= 3.2.0>= 4.0.0, < 4.1.0CVSS 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
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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Determine installed knot resolver versionRun 'knot-resolver --version' or 'kresd --version' on the system. On Fedora, run 'rpm -q knot-resolver' to see the installed package version.Affected if The reported version is lower than 4.1.0 (such as 3.2.0 or any 4.0.x version)
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Confirm DNSSEC validation is configuredInspect the knot resolver configuration files (typically in /etc/knot-resolver/ or /etc/kresd/) for DNSSEC-related settings such as 'trust_anchors', 'dnssec', or 'validate' directives.Affected if DNSSEC trust anchors are defined or DNSSEC validation is explicitly enabled in the configuration
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Verify the resolver forwards NXDOMAIN on validation failureThis requires examining runtime behavior: send a DNS query for a non-existent domain to the resolver and verify whether it returns NXDOMAIN or SERVFAIL when DNSSEC validation should fail. Use 'dig +cd' (checking disabled) to test.Affected if The resolver returns NXDOMAIN to clients instead of SERVFAIL when DNSSEC validation on NXDOMAIN responses should fail
A user is affected if they run any knot resolver version before 4.1.0 and have DNSSEC validation enabled, causing NXDOMAIN responses to be forwarded unsafely instead of generating SERVFAIL on validation failure.
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.
From vendor data4.1.0
Upgrade knot resolver to version 4.1.0 or later to receive the DNSSEC validation fix.
Fix this in Fedora
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-10190 — 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-2019-10190 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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- Version or environment caveats, and links to real fixes
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