Cyber Resilience

CVE-2023-35838

Wireguard 0.5.3

Public PoC
Published
09 August 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 5.7
Click a component to see what it means
Raw vectorCVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS Score 0.0081 54th percentile
Risk Priority 46 floored blend · peak EPSS

Summary

CVE-2023-35838 is a medium-severity Externally Controlled Reference to a Resource in Another Sphere (CWE-610) vulnerability in Wireguard Wireguard. Its CVSS base score is 5.7 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked in the top 46% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

The WireGuard client 0.5.3 on Windows insecurely configures the operating system and firewall such that traffic to a local network that uses non-RFC1918 IP addresses is blocked. This allows an adversary to trick the victim into blocking IP traffic to…

more

selected IP addresses and services even while the VPN is enabled. NOTE: the tunnelcrack.mathyvanhoef.com website uses this CVE ID to refer more generally to "LocalNet attack resulting in the blocking of traffic" rather than to only WireGuard.

CWE(s)
CWE-610

Related Threats

MITRE ATT&CK Enterprise Techniques

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1083 File and Directory Discovery Discovery
Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1552 Unsecured Credentials Credential Access
Adversaries may search compromised systems to find and obtain insecurely stored credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-28722Same product: Microsoft Windows
CVE-2026-28721Same product: Microsoft Windows
CVE-2026-34327Same vendor: Microsoft
CVE-2023-44209Same product: Microsoft Windows
CVE-2023-2984Same product: Microsoft Windows
CVE-2026-47643Same vendor: Microsoft
CVE-2024-38049Same vendor: Microsoft
CVE-2026-41107Same vendor: Microsoft
CVE-2026-32204Same vendor: Microsoft
CVE-2026-40370Same vendor: Microsoft

Affected Assets

wireguard
wireguard
0.5.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SI-22 Information Diversity
addresses: CWE-610

Limits impact of an externally controlled reference to a primary information resource by switching to an identified alternative.

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.

PR.PS-06 mostly match
prevents

Secure development practices directly require input validation and reference sanitization that prevent externally-controlled resource references.

DE.CM-09 partial match
prevents

Runtime monitoring of software and data flows can detect anomalous external resource accesses that result from this weakness.

PR.IR-01 partial match
prevents

Network segmentation and access controls limit the blast radius when an external reference escapes its intended sphere.

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.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect instances of the weakness but does not prevent it at design or coding time.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates validation of all external references to prevent uncontrolled resource access.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for controls against externally supplied resource identifiers.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles reduce the attack surface for externally controlled references but do not prescribe specific validation rules.

A.8.28 Secure coding partial match
prevents

Secure coding standards require input validation and canonicalization to block externally controlled resource references.

A.8.3 Information access restriction partial match
mitigates

Information access restriction limits what resources can be reached, indirectly reducing impact of external references.

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 (1 rule)
  • V-248577 OL 8 must enable kernel parameters to enforce Discretionary Access Control (DAC) on symlinks. prevents CWE-610

References