Security readout for executives and security teams
Plain-English summary
Affected camera firmware can be knocked into a state where legitimate users cannot log in. The reported impact is availability only, not data theft or device takeover. Because exploitation is remote and unauthenticated, internet-exposed management interfaces raise business risk.
Executive priority
Treat as high priority for sites relying on these cameras for safety, operations, or physical security monitoring. The main business risk is loss of administrative access and disrupted camera management, especially when camera interfaces are remotely reachable.
Technical view
CVE-2021-40406 is a denial-of-service flaw in Reolink RLC-410W v3.0.0.136_20121102 cgiserver.cgi session creation. The CVSS vector is network, low complexity, no privileges, no user interaction, with high availability impact and no stated confidentiality or integrity impact.
Likely exposure
Evidence supports exposure for Reolink RLC-410W cameras running firmware v3.0.0.136_20121102. The source bundle does not name other affected models, versions, CPEs, or downstream products.
Exploitation context
The CVE states an attacker can send a specially crafted HTTP request to trigger login denial. CISA KEV is false in the bundle, and no cited source here supports active exploitation in the wild.
Researcher notes
The public evidence is narrow: one model, one firmware build, denial of service, and CWE-400. The bundle does not provide patch status, broader version ranges, exploit maturity, or active exploitation evidence, so avoid overgeneralizing exposure.
Mitigation direction
- Identify and prioritize affected Reolink RLC-410W cameras.
- Check Reolink or Talos guidance for fixed firmware or vendor mitigations.
- Restrict camera management interfaces from the internet.
- Limit management access to trusted networks or VPN.
- Monitor camera availability and authentication failure patterns.
Validation and detection
- Inventory camera model and firmware version.
- Confirm whether cgiserver.cgi management access is reachable from untrusted networks.
- Review security monitoring for abnormal login denial or availability events.
- Verify any vendor-recommended update or mitigation is applied.
- Document compensating controls where no patch is confirmed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-400: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-40406 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.5HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://talosintelligence.com/vulnerability_reports/TALOS-2021-1423CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.