Security readout for executives and security teams
Plain-English summary
A flaw in the TOTOLINK T6 router’s management interface lets an unauthenticated network attacker alter MAC-based device access rules. This could permit unauthorized devices onto a protected network or block legitimate devices, undermining a control administrators may rely upon.
Executive priority
Treat affected, untrusted-network-reachable devices as an immediate remediation priority. Restrict management exposure now, then verify vendor-supported firmware or replacement options. Internally isolated devices still require prompt review because compromised hosts could reach the vulnerable interface.
Technical view
CVE-2026-51701 is an incorrect access-control vulnerability (CWE-284) in setMacFilterRules on TOTOLINK T6 firmware 4.1.5cu.748_B20211015. A crafted POST request to /cgi-bin/cstecgi.cgi can change access-control settings without authentication. CVSS 3.1 rates it 9.1: network-accessible, low complexity, no privileges, and no user interaction.
Likely exposure
Confirmed scope is limited to TOTOLINK T6 firmware 4.1.5cu.748_B20211015. Risk depends on whether the management endpoint is reachable from untrusted networks, including the internet, guest networks, or compromised internal devices. The supplied structured affected-product fields are incomplete, so broader version exposure is unknown.
Exploitation context
The supplied sources describe an unauthenticated network attack requiring a crafted POST request. The CVE is not listed as KEV in the bundle, and no cited source establishes active exploitation. Public technical references may increase researcher and attacker awareness, but exploitation prevalence remains unknown.
Researcher notes
The description identifies the vulnerable function, endpoint, request method, exact model, and firmware. It does not establish the complete affected-version range, patch status, default reachability, logging coverage, or exploitation in the wild. Validation should remain non-destructive and avoid changing production access-control rules.
Mitigation direction
- Inventory TOTOLINK T6 devices and identify those running the named firmware version.
- Check TOTOLINK guidance and firmware downloads for an official corrected release.
- Restrict management-interface access to trusted administrative networks only.
- Disable internet-facing remote management where operationally possible.
- Segment or replace affected devices if no vendor-supported correction is available.
Validation and detection
- Verify each T6 device model and installed firmware through trusted administrative records or its management interface.
- Confirm /cgi-bin/cstecgi.cgi is unreachable from internet, guest, and other untrusted network segments.
- Review MAC-filter rules for unexplained additions, removals, or policy changes.
- Review available device and network logs for unexpected management requests or configuration changes.
- After remediation, confirm the installed firmware matches current TOTOLINK guidance.
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-2026-51701 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
- 9.1 (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:N
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:N3.95.2CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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.
CWE mapping pending import
This CVE carries a CWE mapping that will resolve to a full Glexia CWE intelligence page after the official CWE import is complete.