CVE-2021-33045
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 · uneditedThe identity authentication bypass vulnerability found in some Dahua products during the login process. Attackers can bypass device identity authentication by constructing malicious data packets.
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 confidenceAuthentication bypass vulnerability in Dahua surveillance products allowing attackers to circumvent identity verification during the login process by crafting malicious data packets. This critical flaw (CVSS 9.8) enables unauthenticated attackers to gain unauthorized access to affected devices.
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< 2.820.0000000.5.r.210705< 2.800.0000000.29.r.210630< 2.820.0000000.5.r.210705< 4.001.0000005.1.r.210709< 4.001.0000000.1.r.210710< 4.001.0000005.1.r.210713< 4.001.0000000.0.r.210710< 4.001.0000001.1.r.210716CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 device model and typeAccess the device web interface or check the device label to determine if it is an IPC (IP Camera) or NVR (Network Video Recorder) and note the specific model series (e.g., Hum7xxx, Hx3xxx, Nvr 1xxx, Nvr 2xxx, etc.)Affected if The device model matches one of the affected series: Hum7xxx, Hx3xxx, Hx5xxx, Nvr 1xxx, Nvr 2xxx, Nvr 4xxx, Nvr 5xxx, or Nvr 6xx
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Determine firmware versionLog into the device web interface and navigate to the System or About section to view the firmware version, or use the device's API/SDK documentation to query the firmware version programmaticallyAffected if The installed firmware version falls below the fixed versions: Hum7xxx/Hx5xxx < 2.820.0000000.5.r.210705, Hx3xxx < 2.800.0000000.29.r.210630, Nvr 1xxx/4xxx < 4.001.0000005.1.r.210709/713, Nvr 2xxx/5xxx < 4.001.0000000.1.r.210710, Nvr 6xx < 4.001.0000001.1.r.210716
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Verify network exposureCheck if the device management interface (HTTP/HTTPS ports typically 80/443) is accessible from untrusted networks, or review firewall rules and port forwarding configurations that expose the device to external networksAffected if The device login interface is reachable from networks outside the trusted local network, making it exploitable via malicious authentication packets
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Review authentication logsExamine device security logs for failed and successful authentication attempts, looking for unusual login patterns, multiple rapid attempts, or logins from unexpected source IP addressesAffected if There are unexplained authentication events or successful logins that cannot be attributed to legitimate administrators
The device is affected if it is a Dahua IPC or NVR from the listed series, is running firmware version lower than the specified fixed versions, and has its management interface accessible over a network.
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 · scoped2.800.0000000.29.r.2106302.820.0000000.5.r.2107054.001.0000000.0.r.210710
Apply vendor-supplied firmware updates immediately. Until patches are available, isolate affected devices behind firewalls, restrict network access, and monitor for suspicious authentication attempts.
Ipc Hum7xxx: 2.820.0000000.5.r.210705 or later | Ipc Hx3xxx: 2.800.0000000.29.r.210630 or later | Ipc Hx5xxx: 2.820.0000000.5.r.210705 or later | Nvr 1xxx: 4.001.0000005.1.r.210709 or later | Nvr 2xxx: 4.001.0000000.1.r.210710 or later | Nvr 4xxx: 4.001.0000005.1.r.210713 or later | Nvr 5xxx: 4.001.
- 1. Identify the exact model number (e.g., Hum7xxx, Hx3xxx, Hx5xxx, Nvr 1xxx, Nvr 2xxx, Nvr 4xxx, Nvr 5xxx, Nvr 6xx) of the affected Dahua device
- 2. Access the device's web interface or use Dahua's configuration tool to check the current firmware version
- 3. Download the appropriate fixed firmware from Dahua's official support website (www.dahuasecurity.com)
- 4. Ensure the device is connected to a stable power source before initiating the firmware upgrade
- 5. Upload the firmware file through the device's web interface or using Dahua's firmware upgrade tool
- 6. Wait for the upgrade process to complete - do not power off the device during this process
- 7. After reboot, verify the new firmware version matches or exceeds the fixed version for your model
- 8. Change all device passwords after the upgrade as a security best practice
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-2021-33045 — 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-2021-33045 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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