CVE-2026-78501

highpriority · track · 34EPSS 0.005 · 45 %ileDEUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.54% (45th) EPSS

CVSS 8.6 · high

Is it mine?

5 products

Check your exposure

Who says so?

3 sources

cert_bund · msrc_csaf · nvd

EPSS · scored 2026-10-26

Improper neutralization of special elements used in a command ('command injection') in Microsoft 365 Copilot's Business Chat allows an unauthorized attacker to disclose information over a network.

cvss

Technical severity, 0–10. One row per scoring source.

8.6

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 4

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:Nprimary · secure@microsoft.com USexploitability 3.9 · impact 4

v3.17.9highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N/E:U/RL:O/RC:Csecondary · Microsoft Security Response Center US

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-77USCWE-77USCWE-923US

affected products (5)

Products and version ranges known to be affected.

Microsoft 365 Copilot 365 Copilot's Business Chatall versionscert_bundDEcpe:/a:microsoft:365_copilot:365_copilots_business_chat
Microsoft 365 Copilot 365 Copilot's Business Chatall versionscert_bundDEcpe:/a:microsoft:365_copilot:-
Microsoft Authenticator for Androidall versionscert_bundDEcpe:/a:microsoft:authenticator:for_android
Microsoft Microsoft 365 Copilot's Business Chatall versionsfixedmsrc_csafUS
microsoft 365 copilot chatall versionsnvdUScpe:2.3:a:microsoft:365_copilot_chat:*:*:*:*:*:*:*:*

advisories (2)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-3457Microsoft Apps (Authenticator und 365 Copilot): Mehrere SchwachstellenDeutsch2026-09-17csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Microsoft Authenticator und Microsoft 365 Copilot ausnutzen, um seine Privilegien zu erhöhen, und um Informationen offenzulegen.
msrc_CVE-2026-78501Microsoft 365 Copilot Business Chat Information Disclosure Vulnerability2026-09-17csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

sources

Which sources assert this record, and when.

cert_bund msrc_csaf nvd NVD CVE.org MITRE

published 2026-09-17modified 2026-10-14

references (1) nvd

External citations — patches, advisories, analysis.

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78501PatchVendor Advisory

scry

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