CVE-2021-40407
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.
do firstThe impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization if a current mitigation is unavailable.
Can a WAF block it? Partly. The attack is delivered via an HTTP request to the SetDdns API with a domain parameter that is not properly validated, allowing command injection. A WAF could partially detect this by matching unusual or suspicious command injection patterns in the domain parameter, but some legitimate domain names might overlap. A custom WAF rule can filter domain parameter in SetDdns API containing command injection syntax, but attackers can vary the request. No tracked WAF vendor has published a rule for this CVE yet.
What a custom rule would match: domain parameter in SetDdns API containing command injection syntax
Also consider: patch · custom WAF rule · shlex/execve-style APIs
Based on an AI reading of the CVE description, and no vendor rule found yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2021-40407 being exploited?
Yes. CVE-2021-40407 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-2021-40407?
CVE-2021-40407 is rated High with a CVSS score of 7.2. 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-2021-40407?
Not known from our data. No patch reference has been recorded for CVE-2021-40407, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2021-40407 affect?
CVE-2021-40407 affects reolink:rlc-410w_firmware. 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.
cisa ssvc
- exploitation
- active
- automatable
- no
- technical impact
- total
Assessed by CISA 21 Dec 2024 (SSVC 2.0.3).
timeline
- 28 Jan 2022Published
- 18 Dec 2024Added to CISA KEV (exploited in the wild) · 1,054 days (about 3 years) later
- 21 Dec 2024CISA SSVC assessment: exploitation active · 3 days later
- 8 Jan 2025CISA remediation due date (US federal agencies) · 18 days later
- 21 Oct 2025CVE record last updated · 287 days (about 10 months) later
- 2 Nov 2026Analysed by vulneraibility.com · 377 days (about 1 year) later
- Linktalosintelligence.com /vulnerability_reports/TALOS-2021-1424
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40407
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
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.