CVE-2026-25791
Unauthenticated Session Allocation in Sliver DNS Listener Causes Memory Exhaustion
Publication date: 2026-02-09
Last updated on: 2026-02-23
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| bishopfox | sliver | to 1.7.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-306 | The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. |
| CWE-400 | The product does not properly control the allocation and maintenance of a limited resource. |
Attack-Flow Graph
AI Powered Q&A
What immediate steps should I take to mitigate this vulnerability?
The vulnerability is fixed in Sliver version 1.7.0. Immediate mitigation involves upgrading Sliver to version 1.7.0 or later.
Can you explain this vulnerability to me?
This vulnerability exists in the Sliver command and control framework versions prior to 1.7.0. The DNS C2 listener accepts unauthenticated TOTP bootstrap messages and allocates server-side DNS sessions without validating the OTP values, even when the EnforceOTP feature is enabled.
Because these sessions are stored without any cleanup or expiry mechanism in this scenario, an unauthenticated remote attacker can repeatedly create sessions, which can lead to memory exhaustion on the server.
This issue was fixed in version 1.7.0 of Sliver.
How can this vulnerability impact me? :
An attacker exploiting this vulnerability can cause memory exhaustion on the server running the vulnerable Sliver framework by repeatedly creating unauthenticated DNS sessions.
This can lead to denial of service (DoS) conditions, potentially making the service unavailable or unstable.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know