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CVE-2026-25791— Sliver has a DNS C2 OTP Bypass Allows Unauthenticated Session Flooding and Denial of Service

Quick assessment

Affected
BishopFox sliver
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Sliver是Bishop Fox开源的一个开源的跨平台对手模拟/红队框架。可以被各种规模的组织用来执行安全测试。 Sliver 1.7.0之前版本存在资源管理错误漏洞，该漏洞源于DNS C2侦听器接受未经验证的TOTP引导消息且未清理会话，可能导致内存耗尽。

CVSS 7.5 · High EPSS 0.55% · P44
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I. Basic Information for CVE-2026-25791

Vulnerability Information
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Vulnerability Title
Sliver has a DNS C2 OTP Bypass Allows Unauthenticated Session Flooding and Denial of Service
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
关键功能的认证机制缺失
Source: CVE Program / CVE List V5
Vulnerability Title
Sliver 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Sliver是Bishop Fox开源的一个开源的跨平台对手模拟/红队框架。可以被各种规模的组织用来执行安全测试。 Sliver 1.7.0之前版本存在资源管理错误漏洞，该漏洞源于DNS C2侦听器接受未经验证的TOTP引导消息且未清理会话，可能导致内存耗尽。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
BishopFox sliver < 1.7.0 -

II. Public POCs for CVE-2026-25791

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III. Intelligence Information for CVE-2026-25791

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IV. Related Vulnerabilities

Same product: sliver
Same vendor: BishopFox
Same weakness: CWE-306

V. Comments for CVE-2026-25791

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