CVE-2026-25791Public exploitNetwork attack vector

Unauthenticated denial of service via DNS session flooding

Published Feb 9, 2026 · Updated Feb 9, 2026

Uncontrolled resource consumption in Bishop Fox Sliver before 1.7.0 allows remote attackers to interrupt service through DNS requests. The DNS C2 listener routes TOTP bootstrap messages to handleHello, which stores a new server-side session without validating the OTP or expiring the allocation. A reachable, active DNS C2 job is the only gate; repeated unauthenticated queries cause unbounded memory growth and service interruption.

CVSS severity7.5
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in Bishop Fox Sliver before 1.7.0 allows remote attackers to interrupt service through DNS requests. The DNS C2 listener routes TOTP bootstrap messages to handleHello, which stores a new server-side session without validating the OTP or expiring the allocation. A reachable, active DNS C2 job is the only gate; repeated unauthenticated queries cause unbounded memory growth and service interruption.

The record

CVE
CVE-2026-25791
Published
Feb 9, 2026
Updated
Feb 9, 2026
Vendor
Bishop Fox
Product
Sliver
Classifications
CWE-400, CWE-306, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.7.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Bishop Fox · Sliverversion=< 1.7.0

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-306Missing Authentication for Critical Function
T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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