CVE-2021-46873Network attack vector

Permanent key denial via future handshake timestamp

Published Jan 29, 2023 · Updated Mar 28, 2025

Denial of service in WireGuard 0.5.3 on Windows allows remote attackers to permanently disable a static private key via manipulated system time. A hijacked unauthenticated NTP source advances the initiator clock, whose TAI64N handshake timestamp becomes the responder's greatest stored value and can be replayed indefinitely. Exploitation requires control of the victim's time source and an initiation message; the affected key can no longer establish its VPN tunnel.

CVSS severity5.3
Medium
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in WireGuard 0.5.3 on Windows allows remote attackers to permanently disable a static private key via manipulated system time. A hijacked unauthenticated NTP source advances the initiator clock, whose TAI64N handshake timestamp becomes the responder's greatest stored value and can be replayed indefinitely. Exploitation requires control of the victim's time source and an initiation message; the affected key can no longer establish its VPN tunnel.

The record

CVE
CVE-2021-46873
Published
Jan 29, 2023
Updated
Mar 28, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 29, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3CanonicalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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