CVE-2023-33285
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 · uneditedAn issue was discovered in Qt 5.x before 5.15.14, 6.x before 6.2.9, and 6.3.x through 6.5.x before 6.5.1. QDnsLookup has a buffer over-read via a crafted reply from a DNS server.
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 confidenceQDnsLookup in Qt has a buffer over-read vulnerability when parsing DNS responses. A remote attacker controlling a malicious DNS server can send a crafted DNS reply that causes the Qt application to read beyond the intended buffer boundary, potentially leading to information disclosure.
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>= 5.0.0, < 5.15.4>= 6.0.0, < 6.2.9>= 6.3.0, < 6.5.1CVSS 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
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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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Check installed Qt versionRun 'qmake --version' or check package manager (dpkg -l | grep qt, rpm -qa | grep qt, or brew list qt), or inspect the Qt libraries bundled with your applicationAffected if The Qt version is 5.0.0 to 5.15.3, 6.0.0 to 6.2.8, or 6.3.0 to 6.5.0
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Search for QDnsLookup usage in source codeGrep your codebase for 'QDnsLookup' imports and class usage: 'grep -r "QDnsLookup" /path/to/source/' or search in your IDEAffected if Your application code explicitly uses the QDnsLookup class for DNS queries
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Check for Qt network module usage that triggers DNS resolutionReview code for QNetworkAccessManager, QNetworkRequest, or any Qt networking classes that perform hostname resolutionAffected if Your application uses Qt network functionality that internally triggers DNS lookups through Qt's resolver
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Verify if DNS responses can be intercepted or controlledAudit network topology and DNS configuration to determine if an attacker could supply malicious DNS responses (e.g., man-in-the-middle on network, compromised DNS server)Affected if Your application performs DNS lookups over untrusted networks where a remote attacker could control the DNS server response
You are affected if your Qt version falls within the vulnerable ranges AND your application uses Qt networking features (specifically QDnsLookup or any Qt code that triggers DNS resolution) that could receive responses from an attacker-controlled DNS server.
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 · scoped5.15.46.2.96.5.1
Upgrade Qt to version 5.15.14, 6.2.9, 6.5.1 or later. If immediate upgrade is not feasible, audit code for QDnsLookup usage and implement application-layer validation of DNS responses before processing.
Qt 5.15.14+ (for 5.x), Qt 6.2.9+ (for 6.0-6.1.x), or Qt 6.5.1+ (for 6.3-6.5.x)
- 1. Identify the current Qt version in use by checking project dependencies or the installed Qt version
- 2. For Qt 5.x users: Upgrade to Qt 5.15.14 or later
- 3. For Qt 6.0.x - 6.1.x users: Upgrade to Qt 6.2.9 or later
- 4. For Qt 6.3.x - 6.5.0 users: Upgrade to Qt 6.5.1 or later
- 5. Rebuild and redeploy the application with the updated Qt libraries
- 6. Verify the fix by testing DNS lookup functionality with the updated Qt version
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-33285 — 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-2023-33285 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
- No weaponised exploit code, or anything meant to cause harm
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