CVE-2023-35838
The WireGuard client 0.5.3 on Windows insecurely configures the operating system and firewall...
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 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.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
5.7
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 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.
- Record
CVE-2023-35838- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-610
- Updated
- 2026-11-02
CVE List No score
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 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.
- Record
CVE-2023-35838- Updated
- 2026-11-02
EUVDEUVD-2023-39833 No score
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 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.
- Record
EUVD-2023-39833- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-q424-r5hc-33qq
5.7
The WireGuard client 0.5.3 on Windows insecurely configures the operating system and firewall...
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 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.
- Record
GHSA-q424-r5hc-33qq- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-610
- Updated
- 2026-11-02
OSVPYSEC-2023-321
5.7
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 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.
- Record
PYSEC-2023-321- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2023-35838
5.7
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 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.
- Record
UBUNTU-CVE-2023-35838- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSV No score
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 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.
- Record
CVE-2023-35838- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
wireguardPyPI |
through 0.5.3, plus listed versions 0.1.00.1.10.1.20.1.30.1.4 Show 10 moreShow less0.1.50.1.60.2.00.2.10.2.20.2.30.2.40.2.50.3.00.4.0 |
None known |
wireguardUbuntu:16.04:LTS |
All versions, plus listed versions 1.0.20200513-1~16.04.11.0.20200513-1~16.04.2 |
None known |
wireguardUbuntu:18.04:LTS |
All versions, plus listed versions 1.0.20200513-1~18.04.11.0.20200513-1~18.04.2 |
None known |
wireguardUbuntu:20.04:LTS |
All versions, plus listed versions 0.0.20190913-1ubuntu10.0.20191212-1ubuntu10.0.20191219-1ubuntu11.0.20200102-1ubuntu11.0.20200121-1ubuntu1 Show 6 moreShow less1.0.20200121-2ubuntu11.0.20200206-1ubuntu11.0.20200206-2ubuntu11.0.20200319-1ubuntu11.0.20200513-1~20.04.11.0.20200513-1~20.04.2 |
None known |
wireguardUbuntu:22.04:LTS |
All versions, plus listed versions 1.0.20210424-1ubuntu11.0.20210914-1ubuntu11.0.20210914-1ubuntu2 |
None known |
wireguardUbuntu:24.04:LTS |
All versions, plus listed versions 1.0.20210914-1ubuntu31.0.20210914-1ubuntu4 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-35838 is a medium vulnerability (CVSS 5.7) in Wireguard, published August 9, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.69%, the 52nd percentile. No source names a fixed version.
References
wireguard.com
tunnelcrack.mathyvanhoef.com/details.html
psirt.global.sonicwall.com/vuln-detail/SNWLID-2023-0015
nvd.nist.gov/vuln/detail/CVE-2023-35838
github.com/advisories/GHSA-q424-r5hc-33qq
github.com/CVEProject/cvelistV5/tree/main/cves/2023/35xxx/CVE-2023-35838.json