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WireguardApplication

CVE-2021-46873

MEDIUM · 5.3 CVSS v3.1 Published 2023-01-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
WireGuard, such as WireGuard 0.5.3 on Windows, does not fully account for the possibility that an adversary might be able to set a victim's system time to a future value, e.g., because unauthenticated NTP is used. This can lead to an outcome in which one static private key becomes permanently useless.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

WireGuard's static key mechanism relies on system time to determine key validity periods. When an attacker can manipulate the system clock forward (e.g., via unauthenticated NTP), the 'birth' timestamp of a static private key can be made to appear in the future relative to the manipulated time, causing the key to become permanently invalidated and unusable.

MitigationDeploy authenticated NTP synchronization (such as NTS - Network Time Security, or TLS-authenticated time sources) to prevent attackers from manipulating system time. Alternatively, implement manual or hardware-based time verification for critical systems.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
WireguardApplication
Affected:= 0.5.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed WireGuard version
    Run 'wg --version' or check the package manager for wireguard-tools version (e.g., dpkg -l wireguard-tools, rpm -qa wireguard-tools)
    Affected if Version equals 0.5.3 exactly (note: this CVE affects only this specific version)
  2. Confirm static key configuration
    Check /etc/wireguard/ for .conf files containing 'PrivateKey' entries that are static (not generated via 'wg genkey'), or examine if wg show interfaces shows persistent static key configurations
    Affected if Static private keys are defined in WireGuard configuration files and are actively used
  3. Verify key birth timestamps
    Run 'wg show <interface>' to display key lifetime information, or use 'wg pubkey' on the private key file to identify it, then inspect if the key's birth time appears to be in the future relative to current system time
    Affected if The 'birth' timestamp of a static key shows as a future date relative to current system time, indicating the key has been invalidated
  4. Check NTP synchronization method
    Review /etc/ntp.conf, /etc/chrony.conf, or systemctl status chronyd/systemd-timesyncd to identify if NTP uses authentication (NTS, TLS) or is unauthenticated
    Affected if System uses unauthenticated NTP (port 123/UDP without NTS, TLS authentication, or similar) allowing potential time manipulation from network attackers

Environment is affected if WireGuard version 0.5.3 is running with static keys while the system relies on unauthenticated NTP, allowing attackers to manipulate system time and permanently invalidate the static key birth timestamp.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Deploy authenticated NTP synchronization (such as NTS - Network Time Security, or TLS-authenticated time sources) to prevent attackers from manipulating system time. Alternatively, implement manual or hardware-based time verification for critical systems.

Recommended fix Moderate confidence

Upgrade to the latest stable release of WireGuard for Windows (version > 0.5.3)

  1. 1. Identify all systems running WireGuard 0.5.3 on Windows.
  2. 2. Backup any existing WireGuard configurations and static private keys before upgrading.
  3. 3. Upgrade WireGuard to the latest available version from the official WireGuard website or package repository.
  4. 4. After upgrading, verify that WireGuard tunnels establish successfully.
  5. 5. If a static private key was previously rendered useless due to this vulnerability, generate a new key pair and update peer configurations accordingly.
Caveat Standard upgrade; no major breaking changes expected for typical configurations

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Wireguard Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-46873 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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