PT-2026-29285 · Sliver+2 · Sliver+2
Skoveit
·
Published
2026-03-31
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Updated
2026-03-31
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CVE-2026-34227
CVSS v3.1
8.8
High
| Vector | AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
Sliver versions prior to 1.7.4
Description
Sliver is a command and control framework that utilizes a custom Wireguard netstack. Prior to version 1.7.4, an unauthenticated attacker can gain immediate, silent control over all active C2 sessions or beacons with a single click on a malicious link. This allows for the exfiltration of collected target data, such as SSH keys and
ntds.dit, or the destruction of the entire compromised infrastructure, all through the operator's browser. The Sliver MCP server, running within the Sliver Client, binds to localhost:8080 by default with a permissive Access-Control-Allow-Origin: * header. This allows cross-origin requests from any arbitrary website to interact with the MCP interface via an operator's browser without credentials. If the interface is misconfigured to bind to all interfaces (0.0.0.0), the vulnerability escalates to direct, unauthenticated remote access. Exploitation grants access to methods like list sessions and beacons, fs ls, fs pwd, fs cd, fs cat, fs rm, fs mv, fs cp, fs mkdir, fs chmod, and fs chown. The root cause is an insecure integration with the mcp-go library, which fails to validate the Content-Type header, allowing attackers to bypass CORS preflight checks. The Sliver implementation also lacks authentication middleware or origin restrictions.Recommendations
Versions prior to 1.7.4 should be updated to version 1.7.4 or later.
Exploit
Fix
Missing Authentication
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Related Identifiers
Affected Products
Sliver
Wireguard
Mcp-Go