CVSS 9.3 · CRITICAL

CVE-2026-33102

Url redirection to untrusted site ('open redirect') in M365 Copilot allows an unauthorized attacker to elevate privileges over a network.

View on NVD

Analysis

Microsoft 365 Copilot is vulnerable to a critical URL redirection flaw that allows attackers to elevate privileges over the network. Organizations using Copilot for Microsoft 365 should ensure they are running the latest versions to prevent unauthorized access to sensitive corporate resources.

Severity

Score: 9.3(CRITICAL)

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

AV: NETWORK

AC: LOW

PR: NONE

UI: REQUIRED

S: CHANGED

C: HIGH

I: HIGH

A: NONE

Weakness (CWE): CWE-601

EPSS

Probability of exploitation (next 30 days): 0.0005 (0.0%)

Percentile: 15.0%

EPSS: 2026-05-06

Affects

microsoft:365_copilot

Technical description

Url redirection to untrusted site ('open redirect') in M365 Copilot allows an unauthorized attacker to elevate privileges over a network.

Published: 4/23/2026, 10:16:37 PM

Last modified: 4/29/2026, 7:04:21 PM

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33102

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.