CVE-2021-33045
CVE-2021-33045 is a security flaw in Dahua IP Camera Firmware, security cameras and video recorders. Attackers can get into Dahua IP Camera Firmware without a valid password. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 21 Aug 2024.[1]
Dahua IP Camera Firmware is in things households have: security cameras and video recorders, so the fix matters at home as much as at work. Dahua has published a fix or advice.
Description
CISA calls it an IP camera authentication bypass in Dahua IP Camera Firmware. In its words: “Dahua IP cameras and related products contain an authentication bypass vulnerability when the loopback device is specified by the client during authentication.”[1]
The underlying weakness is improper authentication (CWE-287), in MITRE’s list of common software weaknesses.[2]
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Dahua’s advisory has them[3]. CISA names the product as Dahua IP Camera Firmware.
Every device with Dahua IP Camera Firmware needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 21 Aug 2024, 1,071 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 11 Sep 2024 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at over 99%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Dahua has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”[1]
- Update Dahua IP Camera Firmware now.Install the latest update from Dahua on every device that has it, and restart when asked. Then turn on automatic updates, so the next fix arrives on its own.
- If the maker has stopped updating it, replace it.Cameras stop getting fixes after a few years, and attackers keep a list of the ones that did. If there’s no newer firmware, it won’t be fixed.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at over 99%.[4] |
See also
Other Dahua IP Camera Firmware flaws
- CVE-2021-33044: IP camera authentication bypass ·
Other improper authentication flaws
- CVE-2026-105133, AhsayCBS: improper authentication ·
- CVE-2026-42018, JFrog Artifactory: improper authentication ·
- CVE-2026-82329, JFrog Artifactory: improper authentication ·
- CVE-2026-59822, BerriAI LiteLLM: improper authentication ·
- CVE-2023-49105, ownCloud: improper authentication ·
Added the same day
- CVE-2022-0185, Linux Kernel: heap-based buffer overflow ·
- CVE-2021-33044, Dahua IP Camera Firmware: IP camera authentication bypass ·
- CVE-2021-31196, Microsoft Exchange Server: information disclosure ·
References
- ^ Cybersecurity and Infrastructure Security Agency. “Dahua IP Camera Authentication Bypass Vulnerability”. Known Exploited Vulnerabilities Catalog, added 21 Aug 2024.
- ^ National Institute of Standards and Technology. “CVE-2021-33045 Detail”. National Vulnerability Database, published 15 Sep 2021.
- ^ Dahua. Advisories and fixes: dahuasecurity.com, dahuasecurity.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.996, percentile 99.9, 31 Oct 2026.
- CVE Program. “CVE-2021-33045”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.