CVE-2026-116748

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.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE

CWE-942

Published

2026-10-26

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

References

• 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

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