CVE-2026-25791

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

HIGH
7.5
CVSS Score
Published: February 9, 2026 at 08:34 PM UTC
Updated: June 17, 2026 at 10:25 AM UTC
1 product affected across 1 vendorSliver

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Severity
HIGH7.5
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.7.0
Affected range stops below 1.7.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/BishopFox/sliver/security/advisories/GHSA-wxrw-gvg8-fqjp
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/BishopFox/sliver/releases/tag/v1.7.0

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-306CWE-400

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