Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-34227 is a medium-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Bishopfox Sliver. Its CVSS base score is 5.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 33th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-14 (Permitted Actions Without Identification or Authentication) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34227 is a high-severity vulnerability (CVSS 3.1 score of 8.8) affecting Sliver, an open-source command and control (C2) framework that implements a custom Wireguard netstack. Versions prior to 1.7.4 are vulnerable due to weaknesses mapped to CWE-306 (Missing Authentication for Critical Function) and CWE-942 (Permissible Navigational Transitions). The flaw enables attackers to hijack C2 operator sessions through the operator's browser without authentication.
An unauthenticated attacker can exploit this vulnerability remotely over the network with low complexity by tricking a Sliver C2 operator into clicking a malicious link (user interaction required). Successful exploitation grants the attacker silent, immediate control over all active C2 sessions and beacons implanted on target systems. This allows full exfiltration of sensitive collected data, such as SSH keys or ntds.dit files, or complete destruction of the compromised infrastructure, all executed client-side in the operator's browser.
The issue was patched in Sliver version 1.7.4, as detailed in the BishopFox security advisory (GHSA-6fpf-248c-m7wm). Operators should upgrade immediately to mitigate risks, particularly given the framework's use in red teaming and adversary emulation where operator browsers may be exposed.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17490
Vulnerability Data
Sliver is a command and control framework that uses a custom Wireguard netstack. Prior to version 1.7.4, a single click on a malicious link gives an unauthenticated attacker immediate, silent control over every active C2 session or beacon, capable of…
more
exfiltrating all collected target data (e.g. SSH keys, ntds.dit) or destroying the entire compromised infrastructure, entirely through the operator's own browser. This issue has been patched in version 1.7.4.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
V3.4.3V3.4.6V6.2.3V6.4.4
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates unique identification and authentication of users before access to functions requiring identity.
Extends the same authentication requirement to non-organizational users accessing critical functionality.
Requires authentication of services before they can invoke or expose critical functions.
Explicitly identifies and limits actions permitted without authentication, preventing critical functions from being exposed.
Information flow enforcement requires approved authorizations and would reject policies permitting untrusted domains.
Access enforcement requires prior authentication before any authorization decision for critical functions.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Directly requires authentication of users/services/hardware, which eliminates missing authentication for critical functions.
Hardened configuration baselines and reviews directly prevent permissive CSP or cross-domain policies.
Secure SDLC activities include review and testing of web security policies to avoid untrusted domains.
Vulnerability identification processes can surface permissive policy misconfigurations.
Managing identities and credentials is a prerequisite for authentication but does not itself enforce it on critical functions.
Defining and enforcing authorizations assumes prior authentication and therefore only partially mitigates the absence of authentication.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
The control explicitly calls for authentication before any critical function is reached, eliminating the possibility of bypassing authentication for high-value operations.
Security testing can detect overly permissive cross-domain policies but does not prevent their initial introduction.
Mandating authentication requirements for critical functions at the requirements-gathering stage ensures that essential operations are not left unprotected by missing login or verification mechanisms.
Network security policies can restrict cross-domain communication but do not specifically mandate strict CSP or cross-domain policy configuration.
Mandating authentication for network services and critical functions stops attackers from invoking sensitive operations without credentials, closing gaps where authentication is absent for important capabilities.
Web filtering can block untrusted domains at the network level, partially mitigating permissive cross-domain policies.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248585 OL 8 must require reauthentication when using the "sudo" command. prevents CWE-306
- V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-306
RHEL 7 (2 rules)
- V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-306
- V-237635 The Red Hat Enterprise Linux operating system must require re-authentication when using the "sudo" command. prevents CWE-306
RHEL 8 (2 rules)
- V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-306
- V-237643 RHEL 8 must require re-authentication when using the "sudo" command. prevents CWE-306