Transmission through 2.92 relies on X-Transmission-Session-Id (which is not a forbidden header for Fetch) for access control, which allows remote attackers to execute arbitrary RPC commands, and consequently write to arbitrary files, via POST requests to /transmission/rpc in conjunction with a DNS rebinding attack.
Severity
CVSS 3.0
8.8 high
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
12% chance of exploitation in the next 30 days; higher than 96% of CVEs (scores of 2026-10-31)