Microsoft Copilot Studio command injection

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.4$5k-$25k0.00

Summaryinfo

A vulnerability identified as critical has been detected in Microsoft Copilot Studio. Affected by this issue is some unknown functionality. Performing a manipulation results in command injection. This vulnerability is cataloged as CVE-2026-21520. It is possible to initiate the attack remotely. There is no exploit available. This product operates as a managed service, which prevents users from maintaining vulnerability countermeasures themselves.

Detailsinfo

A vulnerability was found in Microsoft Copilot Studio (affected version not known). It has been classified as critical. This affects some unknown functionality. The manipulation with an unknown input leads to a command injection vulnerability. CWE is classifying the issue as CWE-77. The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. This is going to have an impact on confidentiality. The summary by CVE is:

Exposure of Sensitive Information to an Unauthorized Actor in Copilot Studio allows a unauthenticated attacker to view sensitive information through network attack vector

It is possible to read the advisory at msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2026-21520 since 12/30/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 01/25/2026). The attack technique deployed by this issue is T1202 according to MITRE ATT&CK.

This product is available as a managed service. Users are not able to maintain vulnerability countermeasures themselves.

The vulnerability is also documented in the databases at CNNVD (CNNVD-202601-3922) and EUVD (EUVD-2026-4504). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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: 6.4

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

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

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Command injection
CWE: CWE-77 / CWE-74 / CWE-707
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Status: 🔍

0-Day Time: 🔒

Timelineinfo

12/30/2025 CVE reserved
01/23/2026 +24 days Advisory disclosed
01/23/2026 +0 days VulDB entry created
01/25/2026 +2 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-21520 (🔒)
GCVE (CVE): GCVE-0-2026-21520
GCVE (VulDB): GCVE-100-342519
EUVD: 🔒
CNNVD: CNNVD-202601-3922 - Microsoft Copilot Studio 安全漏洞

Entryinfo

Created: 01/23/2026 08:11
Updated: 01/25/2026 17:44
Changes: 01/23/2026 08:11 (61), 01/24/2026 01:46 (6), 01/24/2026 17:08 (1), 01/25/2026 17:44 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you need the next level of professionalism?

Upgrade your account now!