What is the CVSS score of CVE-2019-15803?

CVE-2019-15803 has a CVSS 3.1 base score of 9.1 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. EPSS exploitation probability: 1.3%.

Is there a public PoC exploit available for CVE-2019-15803?

Yes, a public proof-of-concept exploit is available for CVE-2019-15803. Prioritise patching immediately. EPSS: 1.3%.

Gs1900 8 Firmware CVE-2019-15803

CRITICAL

Improper Authentication (CWE-287)

2019-11-14 cve@mitre.org

Authentication Bypass Zyxel Gs1900 8 Firmware Gs1900 8Hp Firmware Gs1900 10Hp Firmware Gs1900 16 Firmware Gs1900 24E Firmware Gs1900 24 Firmware Gs1900 24Hp Firmware Gs1900 48 Firmware Gs1900 48Hp Firmware

9.1

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.1 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

CVE Published

Nov 14, 2019 - 21:15 nvd

CRITICAL 9.1

DescriptionNVD

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Through an undocumented sequence of keypresses, undocumented functionality is triggered. A diagnostics shell is triggered via CTRL-ALT-t, which prompts for the password returned by fds_sys_passDebugPasswd_ret(). The firmware contains access control checks that determine if remote users are allowed to access this functionality. The function that performs this check (fds_sys_remoteDebugEnable_ret in libfds.so) always return TRUE with no actual checks performed. The diagnostics menu allows for reading/writing arbitrary registers and various other configuration parameters which are believed to be related to the network interface chips.

AnalysisAI

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Improper Authentication (CWE-287), which allows attackers to bypass authentication mechanisms to gain unauthorized access. An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Through an undocumented sequence of keypresses, undocumented functionality is triggered. A diagnostics shell is triggered via CTRL-ALT-t, which prompts for the password returned by fds_sys_passDebugPasswd_ret(). The firmware contains access control checks that determine if remote users are allowed to access this functionality. The function that performs this check (fds_sys_remoteDebugEnable_ret in libfds.so) always return TRUE with no actual checks performed. The diagnostics menu allows for reading/writing arbitrary registers and various other configuration parameters which are believed to be related to the network interface chips. Affected products include: Zyxel Gs1900-8 Firmware, Zyxel Gs1900-8Hp Firmware, Zyxel Gs1900-10Hp Firmware, Zyxel Gs1900-16 Firmware, Zyxel Gs1900-24E Firmware. Version information: before 2.50.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Implement multi-factor authentication, enforce strong password policies, use proven authentication frameworks.