VulnerabilityPublished 28 Oct 2025Updated 5 Nov 2025

CVE-2025-27093: Sliver · Silver has unrestricted traffic between Wireguard clients

Affects github.com/BishopFox/sliverSource GCVE Database

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Authoritative record:CVE-2025-27093· Medium 6.3

Not known to be exploited · CVSS 6.3 Medium : upgrade to 1.5.44 when convenient.

Data as of 4 Nov 2026, 18:23 UTC

CVSS 3.1 base score

6.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 1.5.44

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade github.com/BishopFox/sliver and github.com/bishopfox/sliver to 1.5.44.

Affected software

Product	Affected	Fixed in
Gogithub.com/BishopFox/sliver	Affected <1.5.44	Fixed in 1.5.44
Gogithub.com/bishopfox/sliver	Affected <1.5.44	Fixed in 1.5.44

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in Sliver version 1.5.44 that addresses this issue. Operators should upgrade to version 1.5.44 or later. The vendor suggests implementing traffic filtering between Wireguard clients with a default-deny policy, differentiating between operator and beacon Wireguard configurations, and restricting traffic to specific one-way flows only when explicitly requested via port forwarding. Until patched, operators should consider these mitigations to reduce risk.

Description

Sliver's custom Wireguard implementation does not restrict traffic between Wireguard clients, allowing unrestricted communication. This design flaw can lead to keypair leakage and unauthorized access to operator services. An attacker who recovers a beacon's Wireguard private key can connect to the Wireguard listener and create new clients, potentially maintaining persistence within the network. The vulnerability affects all Sliver versions with Wireguard functionality prior to 1.5.44.

Impact

Operators' machines are at risk because attackers who gain access to the Wireguard network can exploit vulnerabilities in exposed services to achieve remote code execution or gather sensitive information such as hostnames and SSH signatures. The unrestricted client-to-client traffic increases the attack surface within the Wireguard network, potentially allowing lateral movement and unauthorized access.

Summary

Sliver's Wireguard netstack treats operator and beacon Wireguard configurations equivalently and does not filter traffic between clients connected to the Wireguard listener. This lack of filtering allows clients to freely ping and connect to each other, including accessing services like SSH, RDP, and SMB if they listen on 0.0.0.0. The beacon's Wireguard private key can be extracted from process memory dumps, enabling attackers to generate new Wireguard clients without operator knowledge, thus achieving persistence. The vulnerability is present in all versions before 1.5.44 and is fixed in version 1.5.44.

CWE-284Improper Access Control (opens in a new tab)
Pillar weaknessCWE Top 25 (2025): #19OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Operation
Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
Third Party Javascript Management (opens in a new tab)
Virtual Patching (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V1.4.4 (opens in a new tab)
V1.4.5 (opens in a new tab)
V1.10.1 (opens in a new tab)
Attack patterns
Embedding Scripts within Scripts (opens in a new tab)
Modification of Windows Service Configuration (opens in a new tab)
Malicious Root Certificate (opens in a new tab)
Intent Spoof (opens in a new tab)
WebView Exposure (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2026, 18:23 UTC

WeaknessesCWE-284

Technical details

References

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