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CVE Record

CVE-2026-19815: TOTOLINK A800R firewall.so cstecgi.cgi setParentalRules stack-based overflow

A flaw has been found in TOTOLINK A800R 4.1.2cu.5137_B20200730. Affected by this vulnerability is the function setParentalRules of the file /cgi-bin/cstecgi.cgi of the component firewall.so. Executing a manipulation of the argument urlKeyword can lead to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been published and may be used.

CriticalCVSS 9Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A remotely reachable memory-corruption flaw affects one identified TOTOLINK A800R firmware build. An authenticated attacker could trigger a stack overflow through parental-control settings, potentially compromising the router’s confidentiality, integrity, and availability. Public proof-of-concept material exists, increasing risk, but the supplied sources do not establish active exploitation.

Executive priority

Treat identified affected devices as urgent, prioritizing internet-accessible administration interfaces first. Public proof-of-concept availability raises near-term attack risk, although active exploitation is unconfirmed. Require rapid inventory, exposure reduction, vendor-guidance review, and replacement planning if supported firmware is unavailable.

Technical view

CVE-2026-19815 is a stack-based buffer overflow in firewall.so’s setParentalRules function, invoked through /cgi-bin/cstecgi.cgi. Manipulation of urlKeyword triggers the flaw. The CVSS 2.0 vector indicates network access, low complexity, and single authentication. Only firmware 4.1.2cu.5137_B20200730 is identified as affected.

Likely exposure

Exposure is most concerning where an affected A800R administration interface is reachable from untrusted networks or credentials are compromised. Internal-only devices remain at risk from authenticated users or attackers with network and account access. The bundle does not identify other models or firmware versions as affected.

Exploitation context

Public exploit material is referenced, demonstrating practical research interest and lowering barriers to attempted exploitation. However, the CVE is not listed as KEV in the supplied bundle, and no cited evidence confirms exploitation in the wild. Authentication appears required according to the provided CVSS vector.

Researcher notes

Evidence supports a remotely triggerable authenticated stack overflow involving urlKeyword in setParentalRules. The supplied material does not establish the exact overflow bounds, reliable post-corruption impact, affected-version range beyond one build, patch availability, or observed exploitation. Avoid extrapolating exposure to other TOTOLINK products without further evidence.

Mitigation direction

  • Inventory A800R devices and identify firmware build 4.1.2cu.5137_B20200730.
  • Check TOTOLINK guidance for an updated firmware or vendor-approved remediation.
  • Restrict router administration interfaces to trusted management networks.
  • Disable internet-facing remote administration where operationally feasible.
  • Rotate administrative credentials if compromise is suspected.
  • Consider replacing affected devices if no supported remediation is available.

Validation and detection

  • Confirm device model and exact firmware version through trusted asset records or administration interfaces.
  • Verify management interfaces are not exposed to the public internet.
  • Review access logs for unexpected requests to /cgi-bin/cstecgi.cgi.
  • Review administrative accounts and parental-control configuration for unauthorized changes.
  • Confirm any vendor update is installed and persists after reboot.
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

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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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-2026-19815 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 (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

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
9CVSS 2.0CriticalAV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR810VulDB
8.8CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R2.85.9VulDB
8.8CVSS 3.0HighCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R2.85.9VulDB
8.7CVSS 4.0HighCVSS: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——VulDB

Vulnerability scoring details

Base CVSS 4.0 score

8.7High
CVSS 4.0 vector shape for CVE-2026-19815Attack 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:N/SI:N/SA:N/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. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  3. Source timelineVulDB

    VulDB entry created

  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
TOTOLINKA800R4.1.2cu.5137_B20200730Listed
Weakness

CWE details

CWE-119CWE-121

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