Input validation error in ZyXEL Communications Corp. products - #VU49097

Vulnerability identifier: #VU49097

CSH Severity: High

CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: N/A

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to insufficient validation of user-supplied input when processing HTTP requests in zhttpd webserver. A remote attacker can send specially crafted HTTP request to the affected device and execute arbitrary code on the system.

Successful exploitation of the vulnerability will result in a complete compromise of the router.

VMG4005-B50B
VMG8924-B10D
VMG3927-B50B
VMG4927-B50A
EMG6726-B10A
VMG3925-B10B/B10C
EX5510-B0
XMG8825-B50A
XMG3927-B50A
VMG8825-B50A_B60A
VMG3927-B50A_B60A
VMG8825-Bx0B
EX3510-B0
EMG3525-T50B
EMG5523-T50B
VMG1312-T20B
VMG8623-T50B
VMG3625-T50B
VMG3927-T50K
EMG5723-T50K
VMG8825-T50K

Install updates from vendor's website.

Note, some of the firmware updates are scheduled to be released during 2021.

VMG4005-B50B - update to V5.13(ABRL.5)C0
VMG8924-B10D - update to V5.13(ABGQ.6)C0
VMG3927-B50B - update to V5.13(ABLY.6)C0
VMG4927-B50A - update to V5.13(ABLY.6)C0
EMG6726-B10A - update to V5.13 (ABNP.6).C0
VMG3925-B10B/B10C - update to V5.13(AAVF.16)C0
EX5510-B0 - update to V5.15(ABQX.3)C0
XMG8825-B50A - update to V5.15(ABMT.5)C0
XMG3927-B50A - update to V5.15(ABMT.5)C0
VMG8825-B50A_B60A - update to V5.15(ABMT.5)C0
VMG3927-B50A_B60A - update to V5.15(ABMT.5)C0
VMG8825-Bx0B - update to V5.15(ABNY.5)C0
EX3510-B0 - update to V5.17(ABUP.3)C0
EMG3525-T50B - addressed in versions V5.50(ABSL.0)b8, V5.50(ABPM.4)C0
EMG5523-T50B - addressed in versions V5.50(ABSL.0)b8, V5.50(ABPM.4)C0
VMG1312-T20B - update to V5.50(ABSB.3)C0
VMG8623-T50B - update to V5.50(ABPM.4)C0
VMG3625-T50B - update to V5.50(ABPM.4)C0
VMG3927-T50K - update to V5.50(ABOM.5)C0
EMG5723-T50K - update to V5.50(ABOM.5)C0
VMG8825-T50K - update to V5.50(ABOM.5)C0

• https://www.zyxel.com/support/Zyxel-security-advisory-for-remote-code-execution-and-denial-of-service-vulnerabilities-of-CPE.shtml

• Remote code execution in Zyxel routers