CVE-2025-27090 Server-Side Request Forgery (SSRF) in sliver teamserver
An attacker can expose the server's IP address via unverified reverse port forwarding in the Sliver teamserver, requiring an upgrade to mitigate.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-27090?
CVE-2025-27090 is a medium-severity server-side request forgery vulnerability in BishopFox sliver, published on 19 Feb 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Sliver is an open source cross-platform adversary emulation/red team framework, it can be used by organizations of all sizes to perform security testing. The reverse port forwarding in sliver teamserver allows the implant to open a reverse tunnel on the sliver teamserver without verifying if the operator instructed the implant to do so. The only impact that has been shown is the exposure of the server's IP address to a third party. This issue has been addressed in version 1.5.43 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
Weakness: CWE-918
Which versions are affected by CVE-2025-27090?
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 | From 1.5.26 | 1.5.43 |
github.com/bishopfox/sliver Go | From 1.5.26 | 1.5.43 |
github.com/bishopfox/sliver Go | From 1.5.26 | 1.5.43 |
Products include Bishopfox Sliver.
How do I fix CVE-2025-27090?
Upgrade github.com/bishopfox/sliver to 1.5.43 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2025-27090 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-27090 exists.
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-2026-25760 Website Path Traversal / Arbitrary File Read (Authenticated) in Sliver
- CVE-2026-34227 Sliver One-Click Remote Access: Insecure CORS & Unauthenticated MCP Interface
- CVE-2026-32941 Sliver Vulnerable to Authenticated OOM via Memory Exhaustion in mTLS/WireGuard Transports
Sources
Also known as GHSA-fh4v-v779-4g2w, GO-2025-3472.