vulnerability

CVE-2021-33044

9.8

Critical

KEV · Exploited in wildEPSS 100%Patch available

The identity authentication bypass vulnerability found in some Dahua products during the login process. Attackers can bypass device identity authentication by constructing malicious data packets.

exploited

Yes, in CISA KEV since 21 Aug 2024fix by 11 Sept 2024 (CISA deadline for US federal agencies)unvetted proof-of-concept code on github

fix

Patch available see the advisory in the references

likelihood

EPSS 100.0%

Published 15 Sept 2021Analysed here 2 Nov 2026CVSS scored by CISA

do firstApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

triage

server-sideruntimeWAF can block: noAV · networkCWE-287· Improper Authentication

Can a WAF block it? No. Authentication bypass is a flaw in the application's logic. The attack requests look like normal traffic, so a WAF has nothing to match on.

Also consider: patch · add auth middleware

Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

cvss vector

attack vectornetworkattack complexitylowprivileges requirednoneuser interactionnonescopeunchangedconfidentialityhighintegrityhighavailabilityhigh

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

common questions

Is CVE-2021-33044 being exploited?

Yes. CVE-2021-33044 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.

How severe is CVE-2021-33044?

CVE-2021-33044 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2021-33044?

Yes. A fix has been recorded for CVE-2021-33044. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2021-33044 affect?

CVE-2021-33044 affects dahuasecurity:ipc-hum7xxx_firmware, dahuasecurity:ipc-hx3xxx_firmware, dahuasecurity:ipc-hx5xxx_firmware, dahuasecurity:sd1a1_firmware, and 15 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary

technical analysis

affected

dahuasecurity:ipc-hum7xxx_firmwaredahuasecurity:ipc-hx3xxx_firmwaredahuasecurity:ipc-hx5xxx_firmwaredahuasecurity:sd1a1_firmwaredahuasecurity:sd22_firmwaredahuasecurity:sd49_firmwaredahuasecurity:sd50_firmwaredahuasecurity:sd52c_firmwaredahuasecurity:sd6al_firmwaredahuasecurity:tpc-bf1241_firmwaredahuasecurity:tpc-bf2221_firmwaredahuasecurity:tpc-bf5x01_firmwaredahuasecurity:tpc-pt8x21b_firmwaredahuasecurity:tpc-sd2221_firmwaredahuasecurity:tpc-sd8x21_firmwaredahuasecurity:vto-65xxx_firmwaredahuasecurity:vto-75x95x_firmwaredahuasecurity:vth-542xh_firmwaredahuasecurity:tpc-bf5x21_firmware

affected versions

Some Dahua IP Camera, Video Intercom, PTZ Dome Camera, Thermal Camera devices

affectedDahua IP Camera devices IPC-HX3XXX, IPC-HX5XXX, and IPC-HUM7XXX, Video Intercom devices VTO75X95X, VTO65XXX, and VTH542XH, PTZ Dome Camera SD1A1, SD22, SD49, SD50, SD52C, and SD6AL, Thermal TPC-BF1241, TPC-BF2221, TPC-SD2221, TPC-BF5XXX, TPC-SD8X21, and TPC-PT8X21B devices Buildtime before June, 2021.

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

public exploits

Unvetted proof-of-concept code on GitHub: 7 GitHub proofs of concept · 1 Nuclei template

Nuclei

Dahua IPC/VTH/VTO - Authentication Bypass · detection template · critical

GitHub proofs of concept

+3 more repositories

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

cisa ssvc

exploitation: active
automatable: yes
technical impact: total

Assessed by CISA 5 Sept 2024 (SSVC 2.0.3).

timeline

15 Sept 2021Published
11 Oct 2021First proof-of-concept repository on GitHub (unvetted) · 25 days later
21 Aug 2024Added to CISA KEV (exploited in the wild) · 1,045 days (about 3 years) later
5 Sept 2024CISA SSVC assessment: exploitation active · 16 days later
11 Sept 2024CISA remediation due date (US federal agencies) · 5 days later
12 Jan 2026CVE record last updated · 489 days (about 1 year) later
2 Nov 2026Analysed by vulneraibility.com · 294 days (about 10 months) later

how to fix

Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.

references

NVD CVE.org CVE Details Source

4 references in the CVE record: 4 links

Linkdahuasecurity.com /support/cybersecurity/details/957
Linkseclists.org /fulldisclosure/2021/Oct/13
Linkpacketstormsecurity.com /files/164423/Dahua-Authentication-Bypass.html
Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33044

sources

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
CISA KEV catalog: exploitation, date added, due date
CISA Vulnrichment (ADP): SSVC decision points
FIRST EPSS: exploit probability and percentile
Nuclei templates: detection templates
PoC-in-GitHub: GitHub repositories that claim a proof of concept
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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