Security readout for executives and security teams
Plain-English summary
CVE-2026-36540 affects Netis AC1200 Router NC21 firmware V4.0.1.4296. A device on the local network could abuse an unauthenticated router endpoint to run operating-system commands. That can let an attacker take control of the router, disrupt connectivity, or use it as a foothold inside the network.
Executive priority
Treat as high priority for sites using this router model, especially shared offices, retail, hospitality, or environments with guest Wi-Fi. Prioritize containment and vendor-fix verification because the router is a network control point.
Technical view
The disclosure describes unauthenticated command injection in /cgi-bin/skk_set.cgi. The password and new_pwd_confirm POST parameters are reportedly passed to the OS shell without sanitization, enabling remote code execution from the LAN. CVSS is 7.3 High, vector AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L, CWE-77.
Likely exposure
Exposure is most likely where Netis NC21 V4.0.1.4296 routers are reachable from untrusted LAN, guest Wi-Fi, or compromised internal devices. The provided sources do not establish internet-facing exposure or additional affected versions.
Exploitation context
The CVE record is not marked in CISA KEV, and the provided sources do not report active exploitation. The described issue has low complexity and no authentication requirement, but the write-up frames access as from the LAN.
Researcher notes
Evidence is based on the CVE description and a public disclosure reference. The affected product metadata in the bundle is incomplete, but the title and description identify Netis AC1200 Router NC21 V4.0.1.4296. No official vendor advisory or patch is cited in the provided sources.
Mitigation direction
- Inventory Netis NC21 routers and confirm firmware versions.
- Check Netis support channels for updated firmware or official mitigation.
- Restrict router management access to trusted administrative networks only.
- Disable or isolate guest and untrusted LAN access to router administration.
- Replace affected devices if no vendor fix is available.
Validation and detection
- Confirm whether any Netis NC21 device runs V4.0.1.4296.
- Review router access controls for LAN-side administrative endpoints.
- Check logs for unexpected POST requests to /cgi-bin/skk_set.cgi.
- Verify guest networks cannot reach router management interfaces.
- Monitor vendor and CVE records for updated remediation details.
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-77: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-36540 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
- 7.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
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.
SSVC decision data
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/sir3ns/cve-disclosure/blob/main/CVE-2026-36540/readme.mdCVE reference, mitre
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.
Improper Neutralization of Special Elements used in a Command ('Command Injection')
Improper Neutralization of Special Elements used in a Command ('Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.