Vulnerability · Published Feb 9, 2026 · Assigned by GitHub_M

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

High 7.5

In plain English

A high-severity missing authentication in sliver from BishopFox. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.4%top 61.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/bishopfox/sliver	1.6.12	GHSA-wxrw-gvg8-fqjp
Go	github.com/bishopfox/sliver	no fix listed	GO-2026-4466

Affected products (as reported)

Vendor	Product	Versions
BishopFox	sliver	< 1.7.0

Weakness: CWE-306, CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/BishopFox/sliver/security/advisories/GHSA-wxrw-gvg8-fqjp x_refsource_CONFIRM
https://github.com/BishopFox/sliver/releases/tag/v1.7.0 x_refsource_MISC