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TI-2026-20855 Aliases CVE-2026-25791GHSA-wxrw-gvg8-fqjp

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

Priority LOW 39CWE-306Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass, Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-306 and CWE-400.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00447 39th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed sliver (BishopFox): 1.7.0github.com/bishopfox/sliver (Go): 1.6.12

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
BishopFoxsliverbefore 1.7.01.7.0Patch availableCNA
—github.com/bishopfox/sliver (Go)before 1.6.121.6.12Patch availableGHSA-wxrw-gvg8-fqjp
  • sliver VendorBishopFox Affected before 1.7.0 Fixed in 1.7.0 Patch available CNA
  • github.com/bishopfox/sliver (Go) Vendor— Affected before 1.6.12 Fixed in 1.6.12 Patch available GHSA-wxrw-gvg8-fqjp

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:bishopfox:sliver:*:*:*:*:*:*:*:*before 1.7.0VulnerableBishopFox
  • cpe:2.3:a:bishopfox:sliver:*:*:*:*:*:*:*:* Versions before 1.7.0 Vulnerable ·BishopFox

Remediation

  • Fix · CNA sliver (BishopFox) Fixed in 1.7.0
  • Fix · GHSA-wxrw-gvg8-fqjp github.com/bishopfox/sliver (Go) Fixed in 1.6.12 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-25791
  2. 2026-10-03 Alias added: GHSA-wxrw-gvg8-fqjp
  3. 2026-10-07 Priority changed: LOW → MEDIUM
  4. 2026-10-25 Priority changed: MEDIUM → LOW

References

Exploit 1

Advisory 1

Other 3

  • TI-2025-19960 Server-Side Request Forgery (SSRF) in sliver teamserver CVSS 4.0MEDIUM 6.9
  • TI-2023-17391 Sliver from v1.5.x to v1.5.39 has an improper cryptographic implementation, which allows… CVSS 3.1HIGH 8.1
  • TI-2026-26522 Sliver One-Click Remote Access: Insecure CORS & Unauthenticated MCP Interface CVSS 4.0MEDIUM 5.9
  • TI-2026-25389 Sliver Vulnerable to Authenticated OOM via Memory Exhaustion in mTLS/WireGuard Transports CVSS 4.0MEDIUM 5.7
  • TI-2026-23367 Sliver: Authenticated Nil-Pointer Dereference in Handlers CVSS 4.0LOW 2.1
  • TI-2026-20827 Website Path Traversal / Arbitrary File Read (Authenticated) in Sliver CVSS 3.1MEDIUM 6.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences