CVE-2023-28436: Tailscale is software for using Wireguard and multi-factor authentication (MFA)

Routine

MEDIUM 5.7UPGRADE

CVE-2023-28436 is a medium-severity flaw (CVSS 5.7) affecting tailscale. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Tailscale is software for using Wireguard and multi-factor authentication (MFA). A vulnerability identified in the implementation of Tailscale SSH starting in version 1.34.0 and prior to prior to 1.38.2 in FreeBSD allows commands to be run with a higher privilege group ID than that specified in Tailscale SSH access rules. A difference in the behavior of the FreeBSD `setgroups` system call from POSIX meant that the Tailscale client running on a Fr

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.7 (Medium)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	High
User interaction	Required
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-269
Published	2023-03-23
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: tailscale

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

Am I affected?

Timeline

2023-03-23 20:15 UTCPublished CVE record published
2026-06-17 05:47 UTCUpdated Record last modified

tailscale tailscale UPGRADE

Affected: >= 1.34 and < 1.38.2

Fixed in: 1.38.2

Safe to downgrade to: a release before 1.34

1. Check installed version

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

2. UPGRADE to 1.38.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tailscale

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tailscale

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.34 (Debian / Ubuntu)

apt-cache madison tailscale sudo apt install tailscale=<VERSION_BEFORE_1.34> sudo apt-mark hold tailscale

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list tailscale sudo dnf downgrade tailscale-<VERSION_BEFORE_1.34> sudo dnf versionlock add tailscale

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-2023-28436?

tailscale: upgrade to 1.38.2. Exact commands for each OS are on this page.

Is CVE-2023-28436 being exploited?

CVE-2023-28436 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-2023-28436 affect?

CVE-2023-28436 affects tailscale. Severity is medium (CVSS 5.7). Tailscale is software for using Wireguard and multi-factor authentication (MFA). A vulnerability identified in the implementation of Tailscale SSH starting in version 1.34.0 and prior to prior to 1.38.2 in FreeBSD allows commands to be run

How urgent is CVE-2023-28436?

Priority 30/100. No elevated risk signals yet.

Software pages

WireGuard vulnerabilities

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References

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