CVE-2021-27708

Name: CVE-2021-27708
Creator: NVD / NIST
Published: 2021-04-14T16:15:14.127+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 7.61%

Last modified Jun 17, 2026

CVE-2021-27708 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Command Injection in TOTOLINK X5000R router with firmware v9.1.0u.6118_B20201102, and TOTOLINK A720R router with firmware v4.1.5cu.470_B20200911 allows remote attackers to execute arbitrary OS commands by sending a modified HTTP request. This occurs because the function executes glibc's system function with untrusted input. EPSS estimates a 7.61% chance of exploitation in the next 30 days.

Description

Command Injection in TOTOLINK X5000R router with firmware v9.1.0u.6118_B20201102, and TOTOLINK A720R router with firmware v4.1.5cu.470_B20200911 allows remote attackers to execute arbitrary OS commands by sending a modified HTTP request. This occurs because the function executes glibc's system function with untrusted input. In the function, "command" parameter is directly passed to the attacker, allowing them to control the "command" field to attack the OS.

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

7.61%

93.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-78

Affected Software

Vendor	Product	Versions
Totolink	X5000r Firmware	9.1.0u.6118_b20201102
Totolink	A720r Firmware	4.1.5cu.470_b20200911

References

https://hackmd.io/7FtB06f-SJ-SCfkMYcXYxAExploit, Third Party Advisory
https://hackmd.io/mDgIBvoxSPCZrZiZjfQGhwExploit, Third Party Advisory
https://hackmd.io/7FtB06f-SJ-SCfkMYcXYxAExploit, Third Party Advisory
https://hackmd.io/mDgIBvoxSPCZrZiZjfQGhwExploit, Third Party Advisory

Timeline

Published: Apr 14, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-27708?

How severe is CVE-2021-27708?

CVE-2021-27708 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 7.61% probability of exploitation in the next 30 days.

How do I fix CVE-2021-27708?

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-2021-27708?

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

Scan your code now

Source: NVD / NIST