CVE-2023-35838
CVE-2023-35838 is a medium-severity vulnerability in Wireguard with a CVSS 3.x base score of 5.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-610.
Key facts
- Severity: Medium (CVSS 3.x base score 5.7)
- EPSS exploit prediction: 1% (53rd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-610
- Affected product: Wireguard
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2023-35838?
- 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.
- How severe is CVE-2023-35838?
- CVE-2023-35838 has a CVSS 3.x base score of 5.7, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2023-35838 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2023-35838?
- CVE-2023-35838 affects Wireguard. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2023-35838?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2023-35838 published?
- CVE-2023-35838 was published on 2023-08-09 and last updated on 2026-06-17.
References
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2023-0015
- https://tunnelcrack.mathyvanhoef.com/details.html
- https://wireguard.com
Affected products (1)
- cpe:2.3:a:wireguard:wireguard:0.5.3:*:*:*:*:*:*:*
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