CVE-2026-58371: SeaweedFS < 4.30 - Cross-Origin Information Disclosure via Unvalidated JSONP callback Parameter
SeaweedFS before 4.30 reflects the callback query parameter verbatim into responses served with Content-Type application/javascript in the shared writeJson helper (weed/server/common.go), with no callback-name validation, no X-Content-Type-Options: nosniff header, and no CORS allow-list. Every JSON endpoint that uses writeJson - including the unauthenticated master endpoints /dir/status, /dir/lookup and /cluster/status, the volume server /status, and the filer directory listing, all reachable in the default configuration (no -whiteList, no security.toml, bound to 0.0.0.0) - can therefore be loaded cross-origin via a script tag with a chosen callback, letting a third-party web page read cluster topology, volume server URLs and gRPC ports, file identifiers, and directory listings. Because the callback string is reflected at the start of the body and no nosniff header is sent, MIME-sniffing clients may also interpret the reflected content as HTML.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
SeaweedFSto a version that resolves this vulnerability.Fixed in 4.30 - Compensating control
Ensure JSONP-style callback responses include header(s) to prevent MIME sniffing (e.g., X-Content-Type-Options: nosniff) and validate/allow-list the callback parameter so untrusted callback values are not reflected verbatim at the start of the response body.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-58371?
CVE-2026-58371 has a severity rating of low, with a score of 2.3.
How do I fix CVE-2026-58371?
To fix CVE-2026-58371, upgrade SeaweedFS to version 4.30 or later where the vulnerability has been addressed.
What type of vulnerability is CVE-2026-58371?
CVE-2026-58371 is classified as a Cross-Origin Information Disclosure vulnerability.
What are the potential impacts of CVE-2026-58371?
CVE-2026-58371 may allow attackers to exploit unvalidated JSONP callback parameters, potentially leading to information disclosure.
Which software is affected by CVE-2026-58371?
CVE-2026-58371 affects SeaweedFS versions prior to 4.30.