Information disclosure via auto-run prompt URL
Published Aug 18, 2026 · Updated Aug 25, 2026
Command injection in Microsoft Copilot Web allows remote attackers to read connected-app and Copilot session data via a crafted URL. Copilot accepted an attacker-supplied q prompt from the URL and, when paired with the undocumented autorun=1 parameter, executed it on page load in the victim's authenticated session instead of waiting for an explicit submit action. Exploitation requires the victim to open the link, and demonstrated impact is bounded by data and actions already available to that Copilot session and its connected OAuth-backed apps.
Summary
What happened
Command injection in Microsoft Copilot Web allows remote attackers to read connected-app and Copilot session data via a crafted URL. Copilot accepted an attacker-supplied q prompt from the URL and, when paired with the undocumented autorun=1 parameter, executed it on page load in the victim's authenticated session instead of waiting for an explicit submit action. Exploitation requires the victim to open the link, and demonstrated impact is bounded by data and actions already available to that Copilot session and its connected OAuth-backed apps.
The record
- CVE
- CVE-2026-24301
- Published
- Aug 18, 2026
- Updated
- Aug 25, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-77, T1204.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 18, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- CoSnitch crafted-link proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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