Security readout for executives and security teams
Plain-English summary
A publicly documented flaw affects one identified TOTOLINK A800R firmware release. A remote, authenticated attacker may trigger memory corruption through the router’s management interface, potentially compromising confidentiality, integrity, and availability. Public proof-of-concept material raises urgency, although the supplied evidence does not show active exploitation.
Executive priority
Treat affected, reachable devices as an urgent remediation priority because public proof-of-concept material exists and the stated impact is severe. Prioritize externally manageable routers first. Do not interpret the public exploit reference as proof of active attacks; current exploitation evidence is incomplete.
Technical view
CVE-2026-19814 is a stack-based buffer overflow in setMacQos within firewall.so, reached through /cgi-bin/cstecgi.cgi. Manipulating macAddress affects A800R firmware 4.1.2cu.5137_B20200730. The CVSS v2 vector indicates network access, low complexity, single authentication, and potentially complete confidentiality, integrity, and availability impact.
Likely exposure
Exposure is established only for TOTOLINK A800R firmware 4.1.2cu.5137_B20200730. Risk is greatest where the management interface is reachable from untrusted networks or compromised internal systems. The supplied evidence does not establish whether other firmware versions are affected.
Exploitation context
A public proof of concept is referenced, and the vulnerability can reportedly be initiated remotely. The CVSS vector indicates single authentication is required. CVE-2026-19814 is not listed as KEV in the supplied bundle, and no cited evidence confirms active exploitation.
Researcher notes
The record identifies CWE-119 and CWE-121 and assigns CVSS v2 9.0. Public technical material is referenced, but exploit reliability, achieved execution, broader affected-version range, and a fixed release are not established by the supplied evidence. Avoid intrusive validation on production routers.
Mitigation direction
- Identify A800R devices running the affected firmware.
- Restrict router management access to trusted administrative networks and users.
- Disable internet-facing management access where operationally possible.
- Check TOTOLINK guidance for fixed firmware or vendor-approved mitigation.
- Consider replacing affected devices if no supported remediation is available.
Validation and detection
- Verify device models and firmware versions against the affected release.
- Confirm management interfaces are not exposed to untrusted networks.
- Review administrative access controls and credential hygiene.
- Review device and upstream logs for unusual management requests or crashes.
- Confirm any vendor-recommended firmware update or mitigation remains applied.
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-119: 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 lookupCWE-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.
Open ATT&CK lookupCVE-2026-19814 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 (2.0)
- Known Exploited
- No
- Published
Vector: AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
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
4 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.
AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR810VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R2.85.9VulDBCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R2.85.9VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P——VulDBVulnerability scoring details
Base CVSS 4.0 score
8.7HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
Base CVSS 3.0 score
8.8HighVector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
Base CVSS 2.0 score
9CriticalVector: AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- Source timelineVulDB
Advisory disclosed
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Source timelineVulDB
VulDB entry created
- Source timelineVulDB
VulDB entry last update
- 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
- VDB-389950 | TOTOLINK A800R firewall.so cstecgi.cgi setMacQos stack-based overflowCVE reference, VulDB · vdb-entry, technical-description
- VDB-389950 | CTI Indicators (IOB, IOC, IOA)CVE reference, VulDB · signature, permissions-required
- CVE-2026-19814 | CVE Analysis and ReportCVE reference, VulDB · third-party-advisory
- Submit #869431 | Totolink A800R V4.1.2cu.5137_B20200730 Buffer OverflowCVE reference, VulDB · third-party-advisory
- https://github.com/panda666-888/vuls/blob/main/totolink/a800r/setMacQos.mdCVE reference, VulDB · exploit
- https://www.totolink.net/CVE reference, VulDB · product
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 Restriction of Operations within the Bounds of a Memory Buffer
Improper Restriction of Operations within the Bounds of a Memory Buffer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.