CVE-2021-40407
CVE-2021-40407 is a security flaw in Reolink RLC-410W IP Camera. Attackers can run commands on Reolink RLC-410W IP Camera. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 18 Dec 2024.[1]
Reolink RLC-410W IP Camera is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Reolink has published a fix or advice.
Description
CISA calls it an OS command injection in Reolink RLC-410W IP Camera. In its words: “Reolink RLC-410W IP cameras contain an authenticated OS command injection vulnerability in the device network settings functionality.”[1]
The CVE record adds: “An OS command injection vulnerability exists in the device network settings functionality of reolink RLC-410W v3.0.0.136_20121102. At [1] or [2], based on DDNS type, the ddns->domain variable, that has the value of the domain parameter provided through the SetDdns API, is not validated properly. This would lead to an OS command injection. An attacker can send an HTTP request to trigger this vulnerability.”[2]
The underlying weakness is OS command injection (CWE-78), in MITRE’s list of common software weaknesses.
It scores 7.2 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Reolink’s advisory has them[3]. CISA names the product as Reolink RLC-410W IP Camera.
Most families won’t have Reolink RLC-410W IP Camera; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 18 Dec 2024, 1,055 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 8 Jan 2025 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 48%. That’s in the top 2% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Reolink has published a fix or advice.[3] CISA’s required action: “The impacted product could be end-of-life (EoL) and/or end-of-service (EoS).”[1]
- Check whether you use it.Reolink RLC-410W IP Camera is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 8 Jan 2025 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.2.[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 48%.[4] |
See also
Other Reolink flaws
- CVE-2019-11001, Reolink Multiple IP Cameras: OS command injection ·
Other OS command injection flaws
- CVE-2026-110447, Collabora Online – Built-in CODE Server: online – built-in CODE server OS command injection ·
- CVE-2026-106931, EG Secure Solutions SiteGuard Server Edition: OS command injection ·
- CVE-2026-83549, SonicWall SMA1000 Appliances: OS command injection ·
- CVE-2026-49869, Kestra OSS: OSS OS command injection ·
- CVE-2026-73570, Synacor Zimbra Collaboration Suite (ZCS): OS command injection ·
Added the same day
- CVE-2022-23227, NUUO NVRmini2 Devices: missing authentication ·
- CVE-2019-11001, Reolink Multiple IP Cameras: OS command injection ·
- CVE-2018-14933, NUUO NVRmini Devices: OS command injection ·
References
- ^ Cybersecurity and Infrastructure Security Agency. “Reolink RLC-410W IP Camera OS Command Injection Vulnerability”. Known Exploited Vulnerabilities Catalog, added 18 Dec 2024.
- ^ National Institute of Standards and Technology. “CVE-2021-40407 Detail”. National Vulnerability Database, published 28 Jan 2022.
- ^ Reolink. Advisories and fixes: reolink.com, reolink.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.476, percentile 98.8, 31 Oct 2026.
- CVE Program. “CVE-2021-40407”. 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.