CVE-2021-46873: WireGuard, such as WireGuard 0.5.3 on Windows, does not fully account for the possibility that an adversary mi

Routine

MEDIUM 5.3REMOTEDOWNGRADE

CVE-2021-46873 is a medium-severity flaw (CVSS 5.3) affecting wireguard. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 59%)
CISA exploited list	No
Weakness	CWE-362
Published	2023-01-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: wireguard

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-01-29 23:15 UTCPublished CVE record published
2026-06-17 04:15 UTCUpdated Record last modified

wireguard wireguard DOWNGRADE

Affected: 0.5.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.5.3

1. Check installed version

apt-cache policy wireguard || rpm -q wireguard || wireguard --version

2. No fixed release: DOWNGRADE to a release before 0.5.3 (Debian / Ubuntu)

apt-cache madison wireguard sudo apt install wireguard=<VERSION_BEFORE_0.5.3> sudo apt-mark hold wireguard

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list wireguard sudo dnf downgrade wireguard-<VERSION_BEFORE_0.5.3> sudo dnf versionlock add wireguard

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-46873?

wireguard: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-46873 being exploited?

CVE-2021-46873 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-46873 affect?

CVE-2021-46873 affects wireguard. Severity is medium (CVSS 5.3). 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 outcom

How urgent is CVE-2021-46873?

Priority 34/100. Remotely exploitable, no login, no user action

Software pages

Windows vulnerabilities · WireGuard vulnerabilities

Related CVEs

CVE-2023-35838 MEDIUM 5.7 DOWNGRADE The WireGuard client 0.5.3 on Windows insecurely configures the operating system and firewall such that traffi

References

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