CVE-2026-116748

High

Description

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.

SeverityHigh

CVSS8.8

Exploit probability—

ProductTransmission

PublishedOct 26, 2026

First seenOct 26, 2026

Weakness typeCWE-942CWE-942

How to fix

Update

transmission transmission4.1.3 or later

Patches

Vendor advisories

github.com/transmission/transmission/releases/tag/4.1.3

Affected products

Product	Affected versions	Fixed in
transmission transmission	4.0.0 ≤ v < 4.1.3	4.1.3

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