Strix
26.1K

CVE-2023-28436

HIGHCVSS 8/10EPSS 0.46%

Last modified

CVE-2023-28436 is a high-severity vulnerability rated 8/10 on the CVSS scale. 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. EPSS estimates a 0.46% chance of exploitation in the next 30 days.

Description

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 FreeBSD-based operating system did not appropriately restrict groups on the host when using Tailscale SSH. When accessing a FreeBSD host over Tailscale SSH, the egid of the tailscaled process was used instead of that of the user specified in Tailscale SSH access rules. Tailscale SSH commands may have been run with a higher privilege group ID than that specified in Tailscale SSH access rules if they met all of the following criteria: the destination node was a FreeBSD device with Tailscale SSH enabled; Tailscale SSH access rules permitted access for non-root users; and a non-interactive SSH session was used. Affected users should upgrade to version 1.38.2 to remediate the issue.

Metrics

CVSS 3.1
8/10

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

EPSS Probability
0.46%

36.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
TailscaleTailscale>= 1.34, < 1.38.2

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2023-28436?
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 FreeBSD-based operating system did not appropriately restrict groups on the host when using Tailscale SSH. When accessing a FreeBSD host over Tailscale SSH, the egid of the tailscaled process was used instead of that of the user specified in Tailscale SSH access rules. Tailscale SSH commands may have been run with a higher privilege group ID than that specified in Tailscale SSH access rules if they met all of the following criteria: the destination node was a FreeBSD device with Tailscale SSH enabled; Tailscale SSH access rules permitted access for non-root users; and a non-interactive SSH session was used. Affected users should upgrade to version 1.38.2 to remediate the issue.
How severe is CVE-2023-28436?
CVE-2023-28436 has a CVSS score of 8/10 (HIGH severity). The EPSS model estimates a 0.46% probability of exploitation in the next 30 days.
How do I fix CVE-2023-28436?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2023

View all 2023CVEs →

Are you affected by CVE-2023-28436?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST