Security readout for executives and security teams
Plain-English summary
A flaw in Netis NC63 routers can let an unauthenticated network attacker corrupt device memory through the web interface and potentially take full control as root. Because no user interaction or credentials are required, reachable affected devices present severe confidentiality, integrity, and availability risk.
Executive priority
Treat reachable affected devices as an immediate remediation priority. Inventory and restrict access now, then apply vendor-approved remediation when confirmed. Consider isolation or replacement where exposure cannot be controlled, because successful exploitation could provide root-level device control.
Technical view
NC63 firmware through V3.0.0.3327 reportedly uses widthless sscanf conversions when processing destHost for the ipFilterList=mod action in netis.cgi. Oversized input reaches fixed-size stack buffers before authentication verification, allowing saved stack-state overwrite and potential code execution. The Boa CGI environment runs with root privileges.
Likely exposure
Exposure is highest where an affected NC63 web interface is reachable from untrusted networks. Internally reachable devices also remain vulnerable to attackers with network access. The supplied sources do not establish how many devices are exposed or whether every configuration enables the affected path.
Exploitation context
Public technical and exploit-oriented research is cited, reducing the effort needed for independent reproduction. However, the source bundle marks this CVE as absent from KEV and provides no evidence of active exploitation. Public research availability should not be treated as proof of attacks in the wild.
Researcher notes
The reported root cause is CWE-121 stack-based buffer overflow caused by unbounded parsing before authentication. CVSS 3.1 is 9.8: network-accessible, low complexity, no privileges, no interaction, and high impact. The supplied evidence does not name a patched release, vendor advisory, or confirmed exploitation campaign.
Mitigation direction
- Identify NC63 devices and firmware versions through V3.0.0.3327.
- Check Netis guidance for fixed firmware or an approved mitigation.
- Block untrusted access to the device web interface.
- Restrict management access to dedicated administrative networks.
- Isolate affected devices until authoritative remediation is available.
Validation and detection
- Confirm device model and installed firmware using trusted inventory or management records.
- Verify whether the web interface is reachable from untrusted or user networks.
- Review web logs for unusual requests targeting netis.cgi and the affected action.
- Check affected devices for unexplained configuration changes, instability, or administrative access.
- Confirm network controls prevent unauthorized access after mitigation.
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-121: 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 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 lookupCVE-2026-76071 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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:H/I:H/A:H3.95.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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
- Researcher BlogCVE reference, VulnCheck · technical-description, exploit
- Researcher GitHub RepoCVE reference, VulnCheck · technical-description, exploit
- Product PageCVE reference, VulnCheck · product
- https://www.vulncheck.com/advisories/netis-nc63-stack-buffer-overflow-via-desthost-parameterCVE reference, VulnCheck · third-party-advisory
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.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.