Microsoft 365 Copilots Business Chat special element

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.3$0-$5k0.00

Summaryinfo

A vulnerability was found in Microsoft 365 Copilots Business Chat. It has been rated as problematic. This affects an unknown function. This manipulation causes special element. This vulnerability appears as CVE-2026-26129. The attack may be initiated remotely. There is no available exploit. This product is available as a managed service. Users are not able to maintain vulnerability countermeasures themselves.

Detailsinfo

A vulnerability classified as problematic was found in Microsoft 365 Copilots Business Chat (version unknown). Affected by this vulnerability is an unknown function. The manipulation with an unknown input leads to a special element vulnerability. The CWE definition for the vulnerability is CWE-138. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as control elements or syntactic markers when they are sent to a downstream component. As an impact it is known to affect confidentiality. The summary by CVE is:

Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.

It is possible to read the advisory at msrc.microsoft.com. This vulnerability is known as CVE-2026-26129 since 02/11/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/04/2026).

The vulnerability is also documented in the databases at EUVD (EUVD-2026-28445) and CERT Bund (WID-SEC-2026-1411). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Microsoft 365 Copilot

Productinfo

Type

Vendor

Name

License

Managed Service

  • yes

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (microsoft): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Special element
CWE: CWE-138 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Status: 🔍

0-Day Time: 🔒

Timelineinfo

02/11/2026 CVE reserved
05/08/2026 +85 days Advisory disclosed
05/08/2026 +0 days VulDB entry created
06/04/2026 +27 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-26129 (🔒)
GCVE (CVE): GCVE-0-2026-26129
GCVE (VulDB): GCVE-100-361963
EUVD: 🔒
CERT Bund: WID-SEC-2026-1411 - Microsoft 365 Copilot Business Chat: Mehrere Schwachstellen ermöglichen Offenlegung von Informationen

Entryinfo

Created: 05/08/2026 05:46
Updated: 06/04/2026 14:17
Changes: 05/08/2026 05:46 (61), 05/11/2026 08:06 (7), 05/24/2026 02:53 (1), 06/04/2026 14:17 (1)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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