CVSS 9.8 · CRITICAL

CVE-2026-31255

A command injection vulnerability exists in Tenda AC18 V15.03.05.05_multi. The vulnerability is located in the /goform/SetSambaCfg interface, where improper handling of the guestuser parameter allows attackers to execute arbitrary system commands.

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Analysis

This is a command injection vulnerability in Tenda AC18 router firmware. The prompt instructions explicitly identify Tenda router firmware as vendor-specific hardware that is not relevant to the professional software development focus of the community.

Severity

Score: 9.8(CRITICAL)

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

AV: NETWORK

AC: LOW

PR: NONE

UI: NONE

S: UNCHANGED

C: HIGH

I: HIGH

A: HIGH

Weakness (CWE): CWE-77

EPSS

Probability of exploitation (next 30 days): 0.0021 (0.2%)

Percentile: 43.0%

EPSS: 2026-05-06

Affects

tenda:ac18_firmwaretenda:ac18

Technical description

Published: 4/27/2026, 7:16:47 PM

Last modified: 4/28/2026, 3:16:28 PM

References

How to read this card

Actively exploited

KEV (Known Exploited Vulnerabilities) is CISA's catalog of CVEs confirmed as actively exploited in the real world. If a CVE is on KEV, someone is already using it in attacks.

CVSS 10.0

CVSS 10.0 — máxima severidad teórica. Explotable de forma remota, sin privilegios, con impacto total. Aún no confirmada como explotada en el mundo real, pero parchea ya.

AI-recommended

Un modelo de lenguaje revisó el CVE y consideró que afecta a software ampliamente desplegado o herramientas comunes de desarrollo. Un humano del equipo aprobó la publicación antes de que llegara aquí.

Categorías de impacto que evalúa la IA

widely_deployed_infra — kernel Linux, OpenSSL, glibc, k8s, Docker, nginx, OpenSSH.

popular_dev_tooling — Node.js, Python, Go, React, Next.js, librerías comunes de npm/pip.

common_consumer_software — Chrome, Firefox, Windows, macOS, apps móviles populares.

enterprise_saas — GitHub, GitLab, Atlassian, Salesforce, Cisco, Fortinet, Ivanti.

niche_software — CMS regionales, herramientas de hobby, librerías de poco uso.

not_relevant — firmware específico de proveedor, software descontinuado.

EPSS — EPSS (Exploit Prediction Scoring System) by FIRST.org estimates the probability that a CVE will be exploited in the next 30 days. Range is 0 to 1; very fresh CVEs typically score low until evidence accumulates.