# CVE-2026-129258: Tenda AC18 Firmware Upgrade upgrade data authenticity

Status: published. Published: 2026-11-14. Updated: 2026-11-14.

A vulnerability was identified in Tenda AC18 15.03.05.05_multi/15.03.05.19 Build 6318. Affected by this vulnerability is an unknown functionality of the file /cgi-bin/upgrade of the component Firmware Upgrade Handler. Such manipulation of the argument upgradeFile leads to insufficient verification of data authenticity. The attack may be launched remotely. The exploit is publicly available and might be used.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulDB) — https://github.com/longqx223/Tenda-ac-18-V15.03.05.05-/blob/main/2026-10-19-Tenda-AC18-unsigned-firmware-update-advisory-EN.pdf

## Affected products and versions

- Tenda / AC18: 15.03.05.05_multi (affected); 15.03.05.19 Build 6318 (affected). Source: CNA: VulDB

## Severity and prioritization

- CVSS 4.0: 9.4 (critical); CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P; source: CNA: VulDB

- CVSS 3.1: 9.1 (critical); CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 3.0: 9.1 (critical); CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 2.0: 8.3 (high); AV:N/AC:L/Au:M/C:C/I:C/A:C/E:POC/RL:ND/RC:C; source: CNA: VulDB

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-345

## Exploit evidence

- exploit: https://github.com/longqx223/Tenda-ac-18-V15.03.05.05-/blob/main/2026-10-19-Tenda-AC18-unsigned-firmware-update-advisory-EN.pdf (CNA: VulDB)

## References

- https://vuldb.com/vuln/437295 (CNA: VulDB; vdb-entry, technical-description)

- https://vuldb.com/vuln/437295/cti (CNA: VulDB; signature, permissions-required)

- https://vuldb.com/cve/CVE-2026-129258 (CNA: VulDB; third-party-advisory)

- https://vuldb.com/submit/1043033 (CNA: VulDB; third-party-advisory)

- https://github.com/longqx223/Tenda-ac-18-V15.03.05.05-/blob/main/2026-10-19-Tenda-AC18-unsigned-firmware-update-advisory-EN.pdf (CNA: VulDB; exploit, patch)

- https://www.tenda.com.cn/ (CNA: VulDB; product)

## Provenance

- CNA: VulDB: https://www.cve.org/CVERecord?id=CVE-2026-129258; retrieved 2026-11-14; source updated 2026-11-14

Revision: e03c236794d527e68007b6a1960fbdb95f0ac88f86d98ee39412e1731b682707

Canonical: https://y2.dev/cve/CVE-2026-129258

## 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.