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CVE-2023-35838

The WireGuard client 0.5.3 on Windows insecurely configures the operating system and firewall...

5.7 Medium

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.

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

0.69%Up 0.6 points since Aug 10, 2023
90%50%10%1%

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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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

Affected packages
PackageAffectedFixed
wireguard
PyPI
through 0.5.3, plus listed versions
0.1.00.1.10.1.20.1.30.1.4
Show 10 moreShow less
0.1.50.1.60.2.00.2.10.2.20.2.30.2.40.2.50.3.00.4.0
None known
wireguard
Ubuntu:16.04:LTS
All versions, plus listed versions
1.0.20200513-1~16.04.11.0.20200513-1~16.04.2
None known
wireguard
Ubuntu:18.04:LTS
All versions, plus listed versions
1.0.20200513-1~18.04.11.0.20200513-1~18.04.2
None known
wireguard
Ubuntu: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 less
1.0.20200121-2ubuntu11.0.20200206-1ubuntu11.0.20200206-2ubuntu11.0.20200319-1ubuntu11.0.20200513-1~20.04.11.0.20200513-1~20.04.2
None known
wireguard
Ubuntu:22.04:LTS
All versions, plus listed versions
1.0.20210424-1ubuntu11.0.20210914-1ubuntu11.0.20210914-1ubuntu2
None known
wireguard
Ubuntu:24.04:LTS
All versions, plus listed versions
1.0.20210914-1ubuntu31.0.20210914-1ubuntu4
None known

History

History
WhenChangedSources
2026-11-03aliasesEUVD
2026-11-02createdCVE List, GitHub Advisories, NVD, OSV

References

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