CVE-2026-25791

Sliver has a DNS C2 OTP Bypass Allows Unauthenticated Session Flooding and Denial of Service

State: Published
Severity: 7.5 High
Published: Feb 9, 2026
Updated: Feb 10, 2026
Reserved: Feb 5, 2026

Description

Sliver is a command and control framework that uses a custom Wireguard netstack. Prior to 1.7.0, the DNS C2 listener accepts unauthenticated TOTP bootstrap messages and allocates server-side DNS sessions without validating OTP values, even when EnforceOTP is enabled. Because sessions are stored without a cleanup/expiry path in this flow, an unauthenticated remote actor can repeatedly create sessions and drive memory exhaustion. This vulnerability is fixed in 1.7.0.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	GitHub_M

Weaknesses

CWE-306 Missing Authentication for Critical Function
CWE-400 Uncontrolled Resource Consumption

Affected Products

Product	Versions
sliverBishopFox	< 1.7.0Affected

References

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