CVE-2026-33593
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 client can trigger a divide by zero error leading to crash by sending a crafted DNSCrypt query.
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 confidenceA divide-by-zero error exists in the DNSCrypt server implementation where a malicious client can send a specially crafted query that causes the server to crash. The vulnerability allows an unauthenticated remote client to trigger the condition, resulting in denial of service.
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>= 1.9.0, < 1.9.13>= 2.0.0, < 2.0.4CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify if dnsdist is installedRun 'dnsdist --version' or check package manager for dnsdist installationAffected if dnsdist is not installed on the system
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Check the installed dnsdist versionExecute 'dnsdist --version' and compare the output to the affected ranges: >= 1.9.0 and < 1.9.13, or >= 2.0.0 and < 2.0.4Affected if The installed version falls within either affected range (1.9.0-1.9.12 or 2.0.0-2.0.3)
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Verify if DNSCrypt listener is configuredExamine dnsdist configuration files (typically /etc/dnsdist.conf or dnsdist.conf.d/) for 'addDNSCryptBind' or 'DNSCrypt' related directivesAffected if DNSCrypt binding addresses are configured and the server is listening for DNSCrypt queries
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Confirm network exposure of DNSCrypt serviceReview firewall rules and dnsdist bind configuration to determine if the DNSCrypt listener is accessible from external networksAffected if The DNSCrypt service is reachable from unauthenticated remote clients
A system is affected only if it runs a vulnerable dnsdist version (1.9.0-1.9.12 or 2.0.0-2.0.3) with DNSCrypt feature enabled and accessible to remote clients.
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 · scoped1.9.132.0.4
Until an official patch is available, implement input validation on DNSCrypt queries to reject malformed packets that could trigger the divide-by-zero condition, and consider rate limiting or IP-based restrictions on DNS traffic.
dnsdist 2.0.4 (or latest stable release)
- 1. Identify your current dnsdist version using 'dnsdist --version' or your package manager
- 2. For package-based installations: update your package repository and upgrade dnsdist (e.g., 'apt update && apt upgrade dnsdist' or 'yum update dnsdist')
- 3. For source-based installations: download dnsdist 1.9.13 or 2.0.4 (or later stable) from the official repository and rebuild
- 4. After upgrade, restart the dnsdist service
- 5. Verify the new version is running and DNSCrypt functionality works correctly
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-33593 — 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-2026-33593 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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