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CVE Record

CVE-2026-82616: TOTOLINK NR1800X cstecgi.cgi setUploadSetting stack-based overflow

A vulnerability was found in TOTOLINK NR1800X 9.1.0u.6681_B20230703. Impacted is the function setUploadSetting of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument FileName results in stack-based buffer overflow. The attack can be executed remotely. The exploit has been made public and could be used.

CriticalCVSS 9.9Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A remotely reachable flaw in one NR1800X firmware release can corrupt device memory when a privileged user submits a crafted filename. Successful abuse could seriously disrupt or compromise the router. Public exploit material increases urgency, but the supplied sources do not establish active exploitation or identify a vendor fix.

Executive priority

Treat as an urgent exposure-reduction issue, especially for internet-accessible management interfaces. Inventory affected devices immediately, restrict management reachability, and seek vendor remediation. Public exploit material raises near-term risk, although active exploitation is not established by the supplied sources.

Technical view

CVE-2026-82616 is a stack-based buffer overflow in setUploadSetting within /cgi-bin/cstecgi.cgi. The FileName argument triggers the condition on NR1800X firmware 9.1.0u.6681_B20230703. CVSS 3.1 rates it 9.9: network-accessible, low complexity, low privileges, no user interaction, changed scope, and high confidentiality, integrity, and availability impact.

Likely exposure

Exposure is limited by the supplied evidence to TOTOLINK NR1800X devices running firmware 9.1.0u.6681_B20230703. Risk is greatest where the management CGI interface is reachable from untrusted networks or accessible through compromised credentials. The sources do not describe default reachability, configuration prerequisites, or other affected releases.

Exploitation context

A public exploit reference exists, and VulDB states remote exploitation is possible. However, the CVSS vector requires low privileges, and the supplied bundle reports no CISA KEV listing. There is no cited evidence of active exploitation in the wild, observed campaigns, or a reliable public compromise indicator.

Researcher notes

The assessment rests mainly on the CVE record and VulDB reporting. The public PDF may provide technical reproduction details, but they are not repeated here. No vendor advisory, fixed version, patch, named mitigation, campaign evidence, or validated indicators are present in the bundle. Testing should remain authorized and isolated.

Mitigation direction

  • Identify and prioritize NR1800X devices running the specified firmware.
  • Restrict management access to trusted administrative networks and authorized users.
  • Remove management-interface exposure from the public internet where operationally possible.
  • Check TOTOLINK guidance for corrected firmware or vendor-approved mitigation.
  • Consider isolating or replacing affected devices if no supported correction is available.

Validation and detection

  • Confirm device model and exact installed firmware through approved inventory or administration methods.
  • Verify whether /cgi-bin/cstecgi.cgi is reachable from untrusted networks.
  • Review management access controls and identify accounts holding required privileges.
  • Review device and perimeter logs for unusual upload-setting requests or unexplained restarts.
  • Reassess after applying vendor guidance without using the public exploit against production systems.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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 · low confidence lookup

CWE-119: Exact CWE lookup

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cwe · low confidence lookup

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.

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cve · low confidence lookup

CVE-2026-82616 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.9 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R

Official CVE source material

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.

4CVSS vectors
6Timeline events
1ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: total

CVSS vector scores

4 official scores

We 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.

ScoreVersionSeverityVectorExploitImpactSource
9.9CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R3.16VulDB
9.9CVSS 3.0CriticalCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R3.16VulDB
9.4CVSS 4.0CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P——VulDB
9CVSS 2.0CriticalAV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR810VulDB

Vulnerability scoring details

Base CVSS 4.0 score

9.4Critical
CVSS 4.0 vector shape for CVE-2026-82616Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. Source timelineVulDB

    Advisory disclosed

  2. Source timelineVulDB

    VulDB entry created

  3. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  4. Source timelineVulDB

    VulDB entry last update

  5. CVE publishedCVE Program

    The CVE record was published.

  6. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
TOTOLINKNR1800X9.1.0u.6681_B20230703Listed
Weakness

CWE details

CWE-119CWE-121

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-119 · source CWE mapping

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.

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CWE-121 · source CWE mapping

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.

Open CWE intelligenceSame-CWE CVEs