Microsoft Copilot Chat Downstream injection

Summaryinfo

A vulnerability was found in Microsoft Copilot Chat. It has been declared as critical. This issue affects some unknown processing of the component Downstream. Executing a manipulation can lead to injection. This vulnerability is handled as CVE-2026-47644. The attack can be executed remotely. There is not any exploit available. This product is a managed service, so users do not have direct control over vulnerability countermeasures.

Detailsinfo

A vulnerability classified as critical was found in Microsoft Copilot Chat (version now known). This vulnerability affects some unknown processing of the component Downstream. The manipulation with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect confidentiality. CVE summarizes:

Improper neutralization of special elements in output used by a downstream component ('injection') in Copilot Chat (Microsoft Edge) allows an unauthorized attacker to disclose information over a network.

The advisory is shared for download at msrc.microsoft.com. This vulnerability was named CVE-2026-47644 since 05/19/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 06/05/2026). The MITRE ATT&CK project declares the attack technique as T1055.

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

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-34336). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Chat Software

Vendor

• Microsoft

Name

• Copilot Chat

License

• commercial

Managed Service

• yes

Website

• Vendor: https://www.microsoft.com/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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