Unauthenticated action execution via unchecked Host header
Published Aug 11, 2026 · Updated Aug 11, 2026
Host header validation bypass in Google Genkit before 2026-06-18 allows remote attackers to execute registered actions through the Dev UI. The Dev UI server binds to all interfaces, and POST /api/runAction accepts requests without rejecting non-loopback Host values, passing attacker-controlled input and context to manager.runAction. A same-network host can connect directly, while a malicious website requires a developer visit and DNS rebinding; action results and flow traces can disclose prompts, user data, and secrets.
Summary
What happened
Host header validation bypass in Google Genkit before 2026-06-18 allows remote attackers to execute registered actions through the Dev UI. The Dev UI server binds to all interfaces, and POST /api/runAction accepts requests without rejecting non-loopback Host values, passing attacker-controlled input and context to manager.runAction. A same-network host can connect directly, while a malicious website requires a developer visit and DNS rebinding; action results and flow traces can disclose prompts, user data, and secrets.
The record
- CVE
- CVE-2026-67179
- Published
- Aug 11, 2026
- Updated
- Aug 11, 2026
- Vendor
- Google Cloud
- Product
- Genkit
- Classifications
- CWE-644, T1210
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 11, 2026CVE publishedPublication date reported by the CVE source.
- Aug 11, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <2026-06-18
What conditions does exploitation require?
What is affected?
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
- Genkit Dev UI Host-header bypass proof of conceptproof of concept · demonstrated
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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