Transmission 4.0.0 before 4.1.3 contains a permissive CORS vulnerability in handle_request() in rpc-server.cc that exposes the X-Transmission-Session-Id anti-CSRF token to any web origin. Malicious web pages can read the token from the 409 handshake response and replay it to issue RPC calls, enabling script-torrent-done execution, download-dir changes, or torrent and data deletion.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 3
- StatusPublished → Awaiting AnalysisNVD modified 2026-10-27 16:03
- StatusReceived → PublishedNVD modified 2026-10-26 21:52
- First seenCVSS 8.7NVD modified 2026-10-26 22:16
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 7
- https://github.com/transmission/transmission
- https://github.com/transmission/transmission/blob/4.1.2/libtransmission/rpc-server.cc#L560
- https://github.com/transmission/transmission/commit/c6a1bd2017a0fea9c956737c213f23e4b0f7929e
- https://github.com/transmission/transmission/pull/8938
- https://github.com/transmission/transmission/releases/tag/4.1.3
- https://joshua.hu/transmission-cors-rpc-csrf-rce-drive-by-exploit
- https://www.vulncheck.com/advisories/transmission-4.0.0-before-4.1.3-permissive-cors-leaks-rpc-anti-csrf-token