CVE-2026-123201

Description

Buku (bukuserver) through 5.1.1 contains an unauthenticated server-side request forgery vulnerability that allows remote attackers to make the server request internal hosts by supplying a url parameter to /api/fetch_data or /api/network_handle. Attackers can target loopback, private, or cloud metadata IP addresses, which pass the weak is_bad_url() check and follow redirects, to discover internal services and read their page titles, descriptions, and keywords.

References

• https://github.com/jarun/buku/blob/e232ac357cbba22fe69d6d6dfc0d35512a4cd313/buku.py#L4057-L4084
• https://github.com/jarun/buku/blob/e232ac357cbba22fe69d6d6dfc0d35512a4cd313/bukuserver/api.py#L97-L105
• https://github.com/jarun/buku/commit/13f6497afc974f02f1069b760772abe8815d1675
• https://github.com/jarun/buku/issues/910
• https://github.com/jarun/buku/pull/916