Security readout for executives and security teams
Plain-English summary
A flaw in TOTOLINK T6 firmware 4.1.5cu.748_B20211015 may let an unauthenticated network attacker delete static DHCP reservations. This can disrupt address assignments and undermine network configuration integrity without requiring user interaction. The record rates it critical, although public evidence of real-world exploitation or a vendor fix is not provided.
Executive priority
Treat identification and exposure reduction as urgent because the reported path is remotely reachable, unauthenticated, and rated CVSS 9.8. Prioritize externally reachable devices first. Do not interpret the critical score as proof of active attacks; current exploitation and patch availability remain unconfirmed in the supplied sources.
Technical view
The delStaticDhcpRules function reportedly lacks correct access control. A crafted POST request to /cgi-bin/cstecgi.cgi can remove static DHCP reservations without authentication. The record assigns CWE-284 and CVSS 3.1 score 9.8. The supplied structured affected-product fields are unspecified, so conclusions should remain limited to the exact T6 firmware named in the description.
Likely exposure
Potential exposure is limited to TOTOLINK T6 devices running 4.1.5cu.748_B20211015 where the affected CGI management endpoint is reachable by an attacker. Internet-accessible administration presents the clearest concern, but reachable internal devices may also be exposed. The source bundle does not establish how commonly this firmware or configuration is deployed.
Exploitation context
The issue reportedly requires network access but no authentication, privileges, or user interaction. The source bundle marks the CVE as absent from KEV and provides no evidence of active exploitation. Public coordination references exist, but the supplied evidence does not establish exploit maturity, scanning activity, or observed attacks.
Researcher notes
The description names one exact T6 firmware release, while the structured affected vendor, product, versions, and CPE fields are all unspecified. This inconsistency limits reliable asset matching. Validate exposure conservatively and seek current vendor confirmation. Avoid extrapolating impact to other TOTOLINK models or firmware versions without additional evidence.
Mitigation direction
- Inventory TOTOLINK T6 devices and identify those running firmware 4.1.5cu.748_B20211015.
- Prevent untrusted networks from reaching the device management interface and affected CGI endpoint.
- Review TOTOLINK guidance for fixed firmware or vendor-approved mitigations; none is identified in the supplied evidence.
- Back up intended DHCP reservations and monitor them for unauthorized changes.
Validation and detection
- Confirm each T6 device model and firmware version through trusted administrative records or its management interface.
- Verify management interfaces are not exposed to the public internet or untrusted network segments.
- Review device and network logs for unexpected CGI requests or static DHCP reservation changes.
- After remediation, confirm reservations persist and access controls block unauthenticated management requests.
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-284: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2026-51718 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
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:H/I:H/A:H3.95.9CISA-ADPVulnerability scoring details
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
- https://www.totolink.net/home/menu/detail/menu_listtpl/download/id/190/ids/36.htmlCVE reference, mitre
- https://www.totolink.net/CVE reference, mitre
- https://github.com/DarkBoulder/CVE-Vendor-Coordination/blob/main/TOTOLINK/README.mdCVE reference, mitre
- https://github.com/ShengWu00/CVE-Vendor-Coordination/blob/main/TOTOLINK/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 Access Control
Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.