Security readout for executives and security teams
Plain-English summary
A flaw in TOTOLINK T6 firmware allows an unauthenticated attacker who can deliver a crafted MQTT message to disrupt or reset mesh information. This could interfere with mesh operations and force metadata regeneration. The record rates it critical, although the supplied evidence does not establish real-world exploitation or fully explain the claimed confidentiality impact.
Executive priority
Treat confirmed affected devices as urgent, especially in operationally important networks or where MQTT is reachable by untrusted systems. Prioritize inventory, network restriction, and vendor-guidance review. Do not interpret the critical score alone as proof of compromise; investigate telemetry and validate actual reachability.
Technical view
CVE-2026-51762 is an incorrect access-control weakness (CWE-284) in meshInfoKick within the cs_broker component of TOTOLINK T6 firmware 4.1.5cu.748_B20211015. A crafted MQTT message can invoke mesh-state cleanup or regeneration without authentication. CVSS 3.1 is 9.8: 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. Devices are more exposed where untrusted systems can reach cs_broker or its MQTT messaging path. The bundle provides no CPEs, inventory prevalence, default broker reachability, or evidence that other models or firmware versions are affected.
Exploitation context
The supplied record describes unauthenticated exploitation through a crafted MQTT message. It does not provide safe evidence about required network positioning or broker configuration. The CVE is not listed as KEV in the bundle, and no cited source establishes active exploitation, public weaponization, or observed attacks.
Researcher notes
The source bundle has an important inconsistency: its affected-product structure says vendor, product, and versions are unavailable, while the title and description identify TOTOLINK T6 4.1.5cu.748_B20211015. The described action clearly affects mesh state, but the bundle does not explain how the CVSS claims high confidentiality, integrity, and availability impact. No patch version is named.
Mitigation direction
- Identify TOTOLINK T6 devices running firmware 4.1.5cu.748_B20211015.
- Check TOTOLINK guidance for an updated firmware or vendor-approved mitigation.
- Restrict cs_broker and MQTT access to trusted management or mesh systems.
- Segment affected routers from untrusted networks until remediation is confirmed.
- Monitor for unexpected mesh-state cleanup, resets, or metadata regeneration.
Validation and detection
- Confirm each T6 device model and installed firmware version.
- Review network controls governing access to cs_broker and MQTT paths.
- Verify untrusted clients cannot reach the affected messaging service.
- Inspect logs and telemetry for unexplained mesh-state regeneration events.
- After remediation, confirm firmware versions and access restrictions remain effective.
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-2026-51762 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.