Actively exploitedCVSS 9.8 · CRITICAL

CVE-2008-4250

Microsoft Windows contains a buffer overflow vulnerability in the Windows Server Service that allows remote attackers to execute arbitrary code via a crafted RPC request that triggers an overflow during path canonicalization.

View on NVD

Analysis

Microsoft Windows contains a critical pre-authentication remote code execution (RCE) vulnerability in the Server service. An attacker can gain full control of the system via a crafted RPC request; this specific flaw was famously used by the Conficker worm and remains on the CISA KEV list.

Relevant roles

WindowsCyberSecurityBackend

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-94CWE-119

CISA KEV

Added to KEV: 2026-05-20

Federal patch deadline: 2026-06-03

Known ransomware use: Unknown

Required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

EPSS

Probability of exploitation (next 30 days): 0.9208 (92.1%)

Percentile: 99.7%

EPSS: 2026-05-25

Affects

microsoft:windows_2000microsoft:windows_server_2003microsoft:windows_server_2008microsoft:windows_vistamicrosoft:windows_xp

Technical description

The Server service in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and SP2, Vista Gold and SP1, Server 2008, and 7 Pre-Beta allows remote attackers to execute arbitrary code via a crafted RPC request that triggers the overflow during path canonicalization, as exploited in the wild by Gimmiv.A in October 2008, aka "Server Service Vulnerability."

Published: 10/23/2008, 10:00:01 PM

Last modified: 5/21/2026, 12:57:17 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.