CVE-2026-58371 SeaweedFS < 4.30 - Cross-Origin Information Disclosure via Unvalidated JSONP callback Parameter

Q: What is CVE-2026-58371?

CVE-2026-58371 is a low-severity cross-site scripting vulnerability in seaweedfs, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Q: Which versions are affected by CVE-2026-58371?

1 open source package ship an affected version, including seaweedfs.

Q: Is CVE-2026-58371 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58371 exists.

Q: How do I fix CVE-2026-58371?

Upgrade seaweedfs to 4.30.0 or later.

Low 2.3 Published 30 Jun 2026 Updated 14 Jul 2026

Attackers can read sensitive cluster topology and file metadata via JSONP injection in SeaweedFS, potentially leading to further compromise.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2026-58371?

CVE-2026-58371 is a low-severity cross-site scripting vulnerability in seaweedfs, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

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.

Weakness: CWE-79

Which versions are affected by CVE-2026-58371?

1 open source package ship an affected version, including seaweedfs.

Package	Affected	Fixed in
`seaweedfs` Bitnami	All versions	`4.30.0`

How do I fix CVE-2026-58371?

Upgrade seaweedfs to 4.30.0 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-58371 being exploited?