CVE-2026-34227 Sliver One-Click Remote Access: Insecure CORS & Unauthenticated MCP Interface
Unauthenticated attackers can hijack Sliver C2 sessions via a malicious link, enabling data exfiltration or infrastructure destruction through the operator's browser.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-34227?
CVE-2026-34227 is a medium-severity missing authorization vulnerability in BishopFox sliver, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Sliver is a command and control framework that uses a custom Wireguard netstack. Prior to version 1.7.4, a single click on a malicious link gives an unauthenticated attacker immediate, silent control over every active C2 session or beacon, capable of exfiltrating all collected target data (e.g. SSH keys, ntds.dit) or destroying the entire compromised infrastructure, entirely through the operator's own browser. This issue has been patched in version 1.7.4.
Which versions are affected by CVE-2026-34227?
3 open source packages ship an affected version, including github.com/bishopfox/sliver. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/bishopfox/sliver Go | All versions | 1.7.4 |
github.com/bishopfox/sliver Go | All versions | 1.7.4 |
github.com/bishopfox/sliver Go | All versions | 1.7.4 |
Products include Bishopfox Sliver.
How do I fix CVE-2026-34227?
Upgrade github.com/bishopfox/sliver to 1.7.4 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-34227 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34227 exists.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in BishopFox sliver
- CVE-2023-34758 Silver vulnerable to MitM attack against implants due to a cryptography vulnerability
- CVE-2026-25791 Sliver has a DNS C2 OTP Bypass Allows Unauthenticated Session Flooding and Denial of Service
- CVE-2025-27090 Server-Side Request Forgery (SSRF) in sliver teamserver
- CVE-2026-25760 Website Path Traversal / Arbitrary File Read (Authenticated) in Sliver
- CVE-2026-32941 Sliver Vulnerable to Authenticated OOM via Memory Exhaustion in mTLS/WireGuard Transports
Sources
Also known as GHSA-6fpf-248c-m7wm, GO-2026-5175.