CVE-2024-49038Public exploitNetwork attack vector

Cross-tenant token theft via permissive postMessage trust

Published Nov 26, 2024 · Updated Jul 8, 2025

Cross-site scripting in Microsoft Copilot Studio allows remote attackers to steal authentication tokens through Microsoft Teams. The Teams app manifest trusted wildcard domains while isFullTrust enabled postMessage access to the host window, letting attacker-controlled code request a victim's token. Exploitation requires a crafted Teams Meeting App Share request from a guest in another tenant; the stolen token enables actions in the victim's context.

CVSS severity9.3
Critical
EPSS probability0.96%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Microsoft Copilot Studio allows remote attackers to steal authentication tokens through Microsoft Teams. The Teams app manifest trusted wildcard domains while isFullTrust enabled postMessage access to the host window, letting attacker-controlled code request a victim's token. Exploitation requires a crafted Teams Meeting App Share request from a guest in another tenant; the stolen token enables actions in the victim's context.

The record

CVE
CVE-2024-49038
Published
Nov 26, 2024
Updated
Jul 8, 2025
Vendor
Microsoft
Product
Microsoft Copilot Studio
Classifications
CWE-79, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 26, 2024CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=N/A

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Copilot Studioversion=N/A

Published CVSS scores

9.3MicrosoftCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
9.6NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1528Steal Application Access Token

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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