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CVE-2026-25791

Bishopfox Sliver authentication bypass

7.5 HIGHPublic exploitEPSS 0.55%
  1. Published9 Feb 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Bishopfox Sliver< 1.7.0

Remediation

Fixed in
Bishopfox Sliver≥ 1.7.0

References

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Frequently asked

Is CVE-2026-25791 being actively exploited?

CVE-2026-25791 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.55%.

How severe is CVE-2026-25791?

CVE-2026-25791 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.55% probability of exploitation.

Which products are affected by CVE-2026-25791?

Affected products include Bishopfox Sliver.

How do I fix CVE-2026-25791?

Upgrade affected software to a fixed version, for example Bishopfox Sliver 1.7.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-25791 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.