PT-2026-26355 · Microsoft · M365 Copilot

Michael Van Leeuwen · Published 2026-03-19 · Updated 2026-03-22 · CVE-2026-26137

Positive Technologies (AI Summary)

CVSS v3.1

9.9

Critical

Base vector

AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

Name of the Vulnerable Software and Affected Versions Microsoft 365 Copilot's Business Chat (affected versions not specified)

Description An authorized attacker can elevate privileges over a network due to a server-side request forgery (SSRF) issue in Microsoft 365 Copilot's Business Chat. Server-side request forgery occurs when an application allows an attacker to make requests to unintended locations. This can potentially lead to unauthorized access to internal resources or data.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

LPE

SSRF

Weakness Enumeration

CWE-918

Related Identifiers

BDU:2026-03516

CVE-2026-26137

Affected Products

M365 Copilot

References · 8

• https://bdu.fstec.ru/vul/2026-03516 · Security Note
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26137 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-26137 · Security Note
• https://twitter.com/RedPacketSec/status/2034870886881230987 · Twitter Post
• https://twitter.com/ptdbugs/status/2034883970710610240 · Twitter Post
• https://twitter.com/CveFindCom/status/2034747449495941609 · Twitter Post
• https://twitter.com/TheHackerWire/status/2034750839953531122 · Twitter Post
• https://twitter.com/CVEnew/status/2035627043937726903 · Twitter Post