Cross-origin information disclosure via unvalidated JSONP callback
Published Jun 30, 2026 · Updated Jun 30, 2026
Cross-site script inclusion in SeaweedFS before 4.30 allows remote attackers to read cluster metadata through crafted JSONP requests. The shared writeJson helper in weed/server/common.go inserts the callback parameter verbatim before serialized JSON and serves it as application/javascript without a nosniff header. Exploitation requires a victim with network reachability to load an attacker-controlled page; unauthenticated default endpoints expose topology, server addresses, ports, file identifiers, and directory listings.
Summary
What happened
Cross-site script inclusion in SeaweedFS before 4.30 allows remote attackers to read cluster metadata through crafted JSONP requests. The shared writeJson helper in weed/server/common.go inserts the callback parameter verbatim before serialized JSON and serves it as application/javascript without a nosniff header. Exploitation requires a victim with network reachability to load an attacker-controlled page; unauthenticated default endpoints expose topology, server addresses, ports, file identifiers, and directory listings.
The record
- CVE
- CVE-2026-58371
- Published
- Jun 30, 2026
- Updated
- Jun 30, 2026
- Vendor
- SeaweedFS
- Product
- SeaweedFS
- Classifications
- CWE-79
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 30, 2026CVE publishedPublication date reported by the CVE source.
- Jun 30, 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 <4.30
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
- SeaweedFS JSONP cross-origin disclosure PoCproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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