Security readout for executives and security teams
Plain-English summary
A flaw in a specific D-Link DWR-M961 router build may let an unauthenticated remote attacker crash the device or take control by sending oversized input to its setup interface. Successful compromise could expose network traffic, alter router settings, interrupt connectivity, and provide a foothold into connected environments.
Executive priority
Prioritize immediate identification and isolation of affected routers, especially internet-accessible or business-critical devices. Schedule vendor-directed remediation urgently. Although active exploitation is not established, unauthenticated remote command execution with full confidentiality, integrity, and availability impact creates critical business risk.
Technical view
CVE-2026-71958 is a CWE-120 buffer overflow in quicksetup.cgi affecting DWR-M961 hardware C1 with software 1.1.2_C1_202602110044. Oversized test4, ssid2, or username values can cause denial of service or arbitrary command execution. CVSS 3.1 is 9.8: network-accessible, low complexity, no privileges, and no user interaction.
Likely exposure
Exposure is highest where the affected setup interface is reachable from the internet or untrusted networks. Internally reachable devices also present lateral-movement risk. The bundle identifies one exact hardware and software combination, but its structured version field reports “0”; confirm applicability against the vendor advisory and device inventory.
Exploitation context
The vulnerability is remotely reachable and reportedly permits arbitrary command execution or device crashes using crafted input. However, the source bundle marks it absent from KEV and provides no cited evidence of active exploitation. Treat it as readily exploitable in principle, not confirmed exploited in the wild.
Researcher notes
The reported overflow targets three quicksetup.cgi fields and maps to CWE-120. Avoid assuming all DWR-M961 revisions are affected: the narrative specifies hardware C1 and one software build, while the structured affected entry lists version “0.” No patch version, exploit prevalence, or prerequisite interface configuration is established in the supplied bundle.
Mitigation direction
- Identify DWR-M961 hardware C1 devices running software 1.1.2_C1_202602110044.
- Review the D-Link advisory and apply its named vendor update or remediation.
- Restrict management and setup interfaces to trusted administrative networks.
- Disable internet-facing administration where operationally possible.
- Monitor affected routers for configuration changes, crashes, or unexpected administrative activity.
Validation and detection
- Inventory DWR-M961 devices and record hardware and software versions.
- Confirm whether quicksetup.cgi is reachable from internet or untrusted network segments.
- Compare installed software against the version and remediation listed by D-Link.
- Review logs and monitoring data for unexplained restarts or administrative changes.
- After remediation, verify management access remains restricted and the approved software is installed.
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-120: 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 lookupCVE-2026-71958 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
- D-Link AdvisoryCVE reference, VulnCheck · vendor-advisory, patch
- Product WebpageCVE reference, VulnCheck · product
- https://www.vulncheck.com/advisories/d-link-dwr-m961-buffer-overflow-via-quicksetup-cgiCVE 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.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.