# CVE-2026-123958: TOTOLINK CA300-PoE cstecgi.cgi setLanConfig buffer overflow

Status: published. Published: 2026-11-07. Updated: 2026-11-07.

A vulnerability was identified in TOTOLINK CA300-PoE 6.2c.884. The affected element is the function setLanConfig of the file /cgi-bin/cstecgi.cgi. Such manipulation of the argument lanDns/lanSecDns/langType leads to buffer overflow. It is possible to launch the attack remotely. The exploit is publicly available and might be used.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- TOTOLINK / CA300-PoE: 6.2c.884 (affected). Source: CNA: VulDB

## Severity and prioritization

- CVSS 4.0: 9.4 (critical); 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; source: CNA: VulDB

- CVSS 3.1: 9.9 (critical); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 3.0: 9.9 (critical); CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 2.0: 9 (critical); AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:C; source: CNA: VulDB

- CVSS 4.0: 8.6 (high); 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: cna@vuldb.com

- CVSS 3.1: 9.9 (critical); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H; source: NVD: cna@vuldb.com

- CVSS 2.0: 9 (high); AV:N/AC:L/Au:S/C:C/I:C/A:C; source: NVD: cna@vuldb.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-120, CWE-119

## Exploit evidence

- exploit: https://lavender-bicycle-a5a.notion.site/TOTOLINK-CA300-PoE-setLanConfig-3f953a41781f8029941cd21d2cc16db0?source=copy_link (CNA: VulDB)

## References

- https://vuldb.com/vuln/432021 (CNA: VulDB; vdb-entry, technical-description)

- https://vuldb.com/vuln/432021/cti (CNA: VulDB; signature, permissions-required)

- https://vuldb.com/cve/CVE-2026-123958 (CNA: VulDB; third-party-advisory)

- https://vuldb.com/submit/1033673 (CNA: VulDB; third-party-advisory)

- https://lavender-bicycle-a5a.notion.site/TOTOLINK-CA300-PoE-setLanConfig-3f953a41781f8029941cd21d2cc16db0?source=copy_link (CNA: VulDB; exploit)

- https://www.totolink.net/ (CNA: VulDB; product)

- https://lavender-bicycle-a5a.notion.site/TOTOLINK-CA300-PoE-setLanConfig-3f953a41781f8029941cd21d2cc16db0?source=copy_link (cna@vuldb.com)

- https://vuldb.com/cve/CVE-2026-123958 (cna@vuldb.com)

- https://vuldb.com/submit/1033673 (cna@vuldb.com)

- https://vuldb.com/vuln/432021 (cna@vuldb.com)

- https://vuldb.com/vuln/432021/cti (cna@vuldb.com)

- https://www.totolink.net/ (cna@vuldb.com)

## Provenance

- CNA: VulDB: https://www.cve.org/CVERecord?id=CVE-2026-123958; retrieved 2026-11-07; source updated 2026-11-07

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123958; retrieved 2026-11-07; source updated 2026-11-07

Revision: bad6a207d7bb78c95523df8234ea52112c0b3da660f30ddd9d45ac8178d7b547

Canonical: https://y2.dev/cve/CVE-2026-123958

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.