Cross-Space session fixation via shared cookie jar
Published May 27, 2026 · Updated May 27, 2026
Session fixation in Gradio before 6.15.0 allows remote attackers to bind cross-Space requests to attacker-known sessions. The /proxy= route reuses a module-level httpx.AsyncClient whose cookie jar accepts a malicious Space's parent-domain Set-Cookie header and replays it to sibling *.hf.space targets. Exploitation requires control of an HF Space, a deployment that loads it, and user interaction that triggers proxy traffic; legitimate Spaces can then process victim requests in attacker-controlled sessions.
Summary
What happened
Session fixation in Gradio before 6.15.0 allows remote attackers to bind cross-Space requests to attacker-known sessions. The /proxy= route reuses a module-level httpx.AsyncClient whose cookie jar accepts a malicious Space's parent-domain Set-Cookie header and replays it to sibling *.hf.space targets. Exploitation requires control of an HF Space, a deployment that loads it, and user interaction that triggers proxy traffic; legitimate Spaces can then process victim requests in attacker-controlled sessions.
The record
- CVE
- CVE-2026-48545
- Published
- May 27, 2026
- Updated
- May 27, 2026
- Vendor
- Gradio
- Product
- Gradio
- Classifications
- CWE-384
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 27, 2026CVE publishedPublication date reported by the CVE source.
- May 27, 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 <6.15.0
What conditions does exploitation require?
What is affected?
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
- Cross-Space cookie-injection reproductionproof 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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