CVE-2026-116748

Transmission 4.0.0 before 4.1.3 Permissive CORS Leaks RPC Anti-CSRF Token

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.

Affected

transmission

CVSS v4.0 VULNCHECK

8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v4.0 VulnCheck

8.7 HIGHCVSS: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 v3.1 VULNCHECK

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

EPSS

1.25% chance of exploitation in the next 30 days, 69th percentile

Nuclei

medium · CWE-942

Published

2026-10-26

Updated

2026-10-31

Proof-of-concept exploits (1)

• https://joshua.hu/transmission-cors-rpc-csrf-rce-drive-by-exploitfind archive

Nuclei templates (1)

• projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-116748.yamlRepo stars 13262★ · pushed 2026-10-31 · find archive
  1 file

  http/cves/2026/CVE-2026-116748.yaml

CVE references

• transmission/transmissionREFERENCE
• transmission/transmission/blob/4.1.2/libtransmission/rpc-server.cc#L560REFERENCE
• transmission/transmission/commit/c6a1bd2017a0fea9c956737c213f23e4b0f7929ePATCH
• transmission/transmission/pull/8938PATCH
• transmission/transmission/releases/tag/4.1.3REFERENCE
• https://www.vulncheck.com/advisories/transmission-4.0.0-before-4.1.3-permissive-cors-leak…ADVISORY

References

• CVE Record
• NVD entry