CVE-2021-27856

Name: CVE-2021-27856
Creator: NVD / NIST
Published: 2021-12-15T20:15:08.003+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 5.60%

Last modified Jun 17, 2026

CVE-2021-27856 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. FatPipe WARP, IPVPN, and MPVPN software prior to versions 10.1.2r60p91 and 10.2.2r42 includes an account named "cmuser" that has administrative privileges and no password. Older versions of FatPipe software may also be vulnerable. EPSS estimates a 5.60% chance of exploitation in the next 30 days.

Description

FatPipe WARP, IPVPN, and MPVPN software prior to versions 10.1.2r60p91 and 10.2.2r42 includes an account named "cmuser" that has administrative privileges and no password. Older versions of FatPipe software may also be vulnerable. The FatPipe advisory identifier for this vulnerability is FPSA002.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

5.60%

91.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions	Update
Fatpipeinc	Ipvpn Firmware	5.2.0	R34
Fatpipeinc	Ipvpn Firmware	6.1.2	R70p26
Fatpipeinc	Ipvpn Firmware	7.1.2	R39
Fatpipeinc	Ipvpn Firmware	9.1.2	R129
Fatpipeinc	Ipvpn Firmware	10.1.2	R60p10
Fatpipeinc	Ipvpn Firmware	10.2.2	R10
Fatpipeinc	Mpvpn Firmware	5.2.0	R34
Fatpipeinc	Mpvpn Firmware	6.1.2	R70p26
Fatpipeinc	Mpvpn Firmware	7.1.2	R39
Fatpipeinc	Mpvpn Firmware	9.1.2	R129
Fatpipeinc	Mpvpn Firmware	10.1.2	R60p10
Fatpipeinc	Mpvpn Firmware	10.2.2	R10
Fatpipeinc	Warp Firmware	5.2.0	R34
Fatpipeinc	Warp Firmware	6.1.2	R70p26
Fatpipeinc	Warp Firmware	7.1.2	R39
Fatpipeinc	Warp Firmware	9.1.2	R129
Fatpipeinc	Warp Firmware	10.1.2	R60p10
Fatpipeinc	Warp Firmware	10.2.2	R10

References

https://www.fatpipeinc.com/support/cve-list.phpVendor Advisory
https://www.zeroscience.mk/codes/fatpipe_backdoor.txtThird Party Advisory
https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5684.phpThird Party Advisory
https://www.fatpipeinc.com/support/cve-list.phpVendor Advisory
https://www.zeroscience.mk/codes/fatpipe_backdoor.txtThird Party Advisory
https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5684.phpThird Party Advisory

Timeline

Published: Dec 15, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-27856?

How severe is CVE-2021-27856?

CVE-2021-27856 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 5.60% probability of exploitation in the next 30 days.

How do I fix CVE-2021-27856?

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.

Are you affected by CVE-2021-27856?

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

Scan your code now

Source: NVD / NIST