Cross-origin agent access via wildcard CORS
Published Sep 16, 2026 · Updated Sep 16, 2026
Permissive CORS in AG-UI Protocol AG-UI 0.3.0 allows remote attackers to invoke and read agent responses through a malicious website. The create_strands_app factory installs CORSMiddleware with wildcard origins, methods, and headers while exposing its agent endpoint without authentication. Exploitation requires a browser to load attacker-controlled content that can reach the endpoint; successful requests expose SSE output and consume model quota.
Summary
What happened
Permissive CORS in AG-UI Protocol AG-UI 0.3.0 allows remote attackers to invoke and read agent responses through a malicious website. The create_strands_app factory installs CORSMiddleware with wildcard origins, methods, and headers while exposing its agent endpoint without authentication. Exploitation requires a browser to load attacker-controlled content that can reach the endpoint; successful requests expose SSE output and consume model quota.
The record
- CVE
- CVE-2026-92359
- Published
- Sep 16, 2026
- Updated
- Sep 16, 2026
- Vendor
- AG-UI Protocol
- Product
- AG-UI
- Classifications
- CWE-942, T1189
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 16, 2026CVE publishedPublication date reported by the CVE source.
- Sep 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0.3.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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