Permissive CORS Vulnerability in Transmission by Transmission Project
CVE-2026-116748

8.7HIGH

Key Information:

Vendor

Transmission

Status
Transmission
Vendor
CVE Published:
26 October 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-116748?

Transmission versions prior to 4.1.3 are vulnerable to a permissive Cross-Origin Resource Sharing (CORS) issue that compromises the X-Transmission-Session-Id anti-CSRF token. This vulnerability allows attackers to access the token via malicious web pages, enabling them to hijack RPC calls. Consequently, they can perform operations such as executing script-torrent-done commands, modifying download directories, or even deleting torrents and associated data.

Affected Version(s)

transmission 4.0.0 < 4.1.3

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-116748 - Proof of Concept

References

https://github.com/transmission/transmission/pull/8938
issue-trackingpatch
https://github.com/transmission/transmission/commit/c6a1b...
patch
https://github.com/transmission/transmission
product

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Joshua Rogers
ckerr
.